Interesting how little actual gameplay discussion is going on here. It's either bitching or defending it. As for most gatcha, I don't get it. Card game ones, sure, it's a card game but digital, I get that. And at least with Korean MMOs there's ostensibly an MMO under all the cosmetics and frustrating RNG features. But gatcha games would probably be better off if they didn't involve spending money. Case in point would be entire genres that rely on RNG drops for progression. Granted, I could say the same thing for the other examples I listed, any card game simulator with all the cards is probably better, and I know from experience that Terraia is probably better than Maplestory (although I don't know how some of the harder bosses in the latter are so that might actually be fun).
Now, if we're talking making a gatcha game, I've got an idea for one that's fairly fair, potentially could be very popular, and would almost certainly make a ton of money, but it would involve significant netcoding when I don't even know how to code so fuck me then.