It's probably based off LoL really, since I'd imagine a lot of people playing HotS came from there. I've never played, I just know that it also uses the Bronze/Silver/Gold/Plat/Diamond/Master tiers.
It just puts a name to a number as I said before. Just having a mmr value doesn't tell you anything without context into the matter. 4k wouldn't even exist in WoW's Arena mmr system as far as I'm aware, highest used to be 3kish(might have changed, not played in ages). However, it's considered above average in Dota 2, but not the best. Hotslog also displays a mmr too if you just wanted to go by mmr alone. I don't think hotslogs system is bad in that sense, it offers the best of both worlds, the bad part is more that the mmr isn't totally accurate due to not having all of the match data available.
The in game system for HotS is really awful though. Rank hasn't meant anything at all for a long time and it's clear it doesn't coincide with the internal mmr. That definitely is just pointlessly obscuring peoples real skill levels.
It just puts a name to a number as I said before. Just having a mmr value doesn't tell you anything without context into the matter. 4k wouldn't even exist in WoW's Arena mmr system as far as I'm aware, highest used to be 3kish(might have changed, not played in ages). However, it's considered above average in Dota 2, but not the best. Hotslog also displays a mmr too if you just wanted to go by mmr alone. I don't think hotslogs system is bad in that sense, it offers the best of both worlds, the bad part is more that the mmr isn't totally accurate due to not having all of the match data available.
The in game system for HotS is really awful though. Rank hasn't meant anything at all for a long time and it's clear it doesn't coincide with the internal mmr. That definitely is just pointlessly obscuring peoples real skill levels.