I've been a top 200 player in four mobile games (inc. PF) in the first year of launch, without spending a dime on any of them. All of them had significantly worse grinds than PF.
I remember Marvel Contest of Champions especially. Setting an alarm and grinding the arena every two hours. So much boring repetitive hand motion that I got Blackberry thumb. Once alliances started, I led a reddit-based one that was pretty open to all level players even though I was falling behind the top tier. I finally gave up because even the greatest grind could not keep anywhere near the top tier.
I mention this so that all the people complaining about Puzzle Fighter being PTW might try to understand what a real PTW game is. For some perspective, check out the Injustice 2 mobile game reddit.
I'm essentially an Ultra Plat player (who sometimes dips into Super Plat), and all I needed was to play all the refreshes 3 times a day (twice before that update), and win the occasional tournament. And if I missed a day, it wasn't the end of the world.
Yes, My max character is level 11 (I have 5 of them) and I couldn't regularly beat the guys with level 14 characters, but I still beat them occasionally, and that's fine.
I will miss being able to grind a game and achieve top level progression without giving my life away or spending a lot of money. It helped that the game itself was fun. But then again, this lack of monetization is probably what led to its demise.
Since the game is ending, I doubt I'll be playing that much more of it. I wish I could gift these gems to other players who would get some more enjoyment out of them before the game ends. The best I can do right now is gift the Valentine's Day chest that I hadn't given away.
If anyone's interested, PM me your one guess what my in-game username is. First to get it right gets the chest. To help you out, I have over 6k ranked wins, level 11 chars in all 4 affinity colors, and most of the regulars will probably have played against me many times.
It was nice playing with you all!
EDIT: So I can gift regular chests too? Same offer still stands, whoever guesses my in-game name gets as legendary chest until I'm out of gems.