Because in your first response you called the game a currency management simulator with slight action elements, neither of which are true. Currency plays a very small role in your play sessions and action is nearly all that's going on.
Currency doesn't play a very small role in the game, lol. I'm not sure how you can say that with a straight face. EVERYTHING levels up in this game, your character, equipment, ranks, skills, mastery, etc (that's ignoring the way Iso-8 stuff -another currency- affects your character beyond that) And everything leveling up is tied to at least one of the different currencies that are scattered across the different modes or are obtainable in the store. It's not like they level up naturally by themselves in the background, or like you get a limited set number of skill points to distribute around.
Even your ability to play is tied to energy, which could be considered a currency in itself taking into account the ways it can be obtained and exchanged. I've seen it all before. It is the same shell as MAA. And like Noray says, the game is constantly pushing you to obtain more of whatever currencies you need. Splash screens, daily bonuses, message gifts, adding friends for those benefits, etc. Ignoring the big "+" button next to the very visible currencies on most game screens, even next to the "Start Mission" button (which is not a "start mission button" really, but a "- X Energy button") there is a button that takes you directly into the store. Like, right next to it. Every single mission has that.
The bulk of the late missions are the repeatable dailies, bonus, special missions, etc. and your choice of mission will always depend on what currency you want or need at that point in time. Everything (leveling up, mission choice, rewards, logging in every day, the store itself, even the story -Hi ISO-8-,
everything revolves around the currencies required for minimal incremental progression, that's why it is more currency management game than brawler. I don't think that is a completely unfair assessment. When every single aspect of the game revolves around that, it's fair to say currency mechanics are much of the content and quality of the game. Noray is absolutely right about that: strip all that, and you have a game that you are done with in 1 hour or 2: a very simple, flashy brawler with no gameplay related incentives to keep going.
I'm not sure what you want me to say about the quality of the action. The gameplay is not terrible, sure, but there's not much to it and I already described it: you take a team of heroes (not really a team as you only use one at a time), go through small corridors and attack small groups of enemies until you get to the boss who you then kill. You use 3 or 4 abilities to help you in your way and sometimes your other heroes activate like strikers for a quick punch in or you can switch to them and use them as extra HP bars, or a friend's hero can be summoned for a small amount of time to help. It all takes 2-4 minutes to do. Rinse, repeat.
I'm sure there are worse games out there. That's not really the point I was making.