The premium tanks are designed to perform worse than the normal tanks in their respective tier. Credits only become a problem once you reach tier 7 or tier 8. If you have grinded to this tier at this point, I would say it is a fair assumption you actually like the game enough to spend some money on the game, such as getting a Lowe for example to grind credits.
Premium ammo is almost never used in public matches. It is mainly reserved for clan wars, otherwise it is simply a waste of money. Most of the time, people have no idea what they are talking about when they complain about premium ammo in public matches. I been called out on using gold, when in fact, I just know where to hit their tank's weakspot.
Paying money just lessens the grind a bit, but there is nothing you can't obtain by playing entirely free.
Source: Played 6000 battles over 3 years and never bought a monthly/yearly premium account time. Utilizing special events help too. I have a tier 10, tier 9, several tier 7s and 8s, and various other tanks researched and in my garage. I only have a SU-100Y premium tank, which I bought using gold I won from one of their events.
I haven't played in about a year, so I don't know how things are now.
6000 battles and you have
a tier 10

wow
You've played the game more than 99 percent of people ever will and have one tier 10 and one tier 9
In WoT the gameplay is in the variety of playstyles that each tank offers ( hull down style, effective range, angling, speed etc) makes you have to play each tank differently and that is what makes the game good
Unfortunately that variety is behind a massive massive massive grind to unlock
Yes the community has collectively decided not to use premium ammo in pubs (it would be expensive to do so)
I forgot to mention all the hidden pay2win aspects
modules, unlocks (tracks, engine, cannon etc) and especially crew training cost a lot of credits (or gold to get 100 percent crew), and trained crew and modules give you large advantages (especially crew) in the few dozen games an f2p player or someone who 'merely' pays for the monthly subscription would take to unlock their new tank to not shit status (who doesn't remember their is-3 sucking ass until they unlocked the final 60k+exp unlock gun)
It's not a permanent advantage, but it is there for a lot of the time, and it is large.
Somehow that is supposed to make it less shitty?
It's a wonderful game with awesome game mechanics and variety but their f2p system is garbage
You can't just spend a reasonable amount of money and get the game
As I said I've spent several hundreds (t54+ subscription + some free exp conversion + some crew training) and was still stuck in stock tanks a lot of the time and still had to play hundreds of games in my t54 and t34 to get credits for more tanks and more modules and more crew training.
edit: and I forgot the large amount of gold (real money) spent on tank slots!
The game is designed to make you spend more and more and is a lot more expensive than any full priced game and will never give you anywhere near all the content even if you pay a lot.
My point is:
A heavily compromised game design that inconveniences people into paying is never a good f2p system.
dota has a good f2p system, vindictus has a good f2p system, tribes ascend had a good f2p system
The WoT one is awful for gamers
virtual world, anything goes, except fuck you give me (loads of) money! and then still fuck you !
I'll edit in a minute with what tanks I have to show how my 1000 games + 300 euros (or however many it was, I'll tell you when I reinstall) compare to your 6000 matches f2p grind of doom when it comes to unlocked content and advantages
edit:
I was wrong, it's not 1000 battles
I played 9833 battles not counting the few months I played in the beta before release
so to your 'I playd more so I know the game better' , I say 'no u'
I have 3 tier 10 and 7 tier 9s and 61 tanks in total, I assume that as f2p player you only have a few garage slots and have to sell old tanks to have room for new ones (and lose access to the old ones obviously , what a wonderful f2p system isn't it!, I spent easily 40-50 euros on garage slots alone)
that's with paying 300 ish euros...
I quit when they added the secondary crew specialisations , then the grind/crew pay2win rabbithole went too deep for my liking
fuck the f2p system wot uses
edit 2
Just to compare it to LoL for the league players
Imagine if :
For the first several dozen or so games your new champion you bought with IP has a lower view range (fog of war is closer) , takes a lot longer to turn, runs at half the speed and hits for half the damage (and lower attack speed) as well as having lower resistances and armor.
All of this would of course also cripple your ability to earn more IP to upgrade your hero to his full power and how it would make you a liability to your team
Then imagine your summoner abilities would have to be rebought for each champion and cost a lot of IP
You would also have the option to pay for a consumable that makes you hit harder and with a longer range
Imagine that whenever you buy a new champion (even if you buy one with real money) you would have to pay for a slot to put that hero in, you only get a few free slots and they can't be bought with IP
Imagine there were several real money only champions that have their own unique playstyles and that in turn help you earn IP faster when playing with them
Now imagine those champions costing 40-50 fucking dollars each
Imagine deaths in the game having an IP cost, you lose IP as you die (and you will be pretty much cannonfodder while upgrading your champion)
Imagine champions expending IP every time they use an ability
Now imagine certain champions expending so much IP per ability cast that they may spend more IP than they can earn that match
Imagine the IP earnings being designed around subscription based IP boosts, and that you will not really be able to maintain the running cost of some of your champions while affording new champions in a reasonable time
Imagine having to play certain 'earner' champions repeatedly because they are the most efficient at earning you IP to afford the ones you really want to play
I can't imagine a league player not going fuuuuuuuuuuuuuck all of that shit upon reading the above, and LoL itself isn't the best f2p system to begin with.