Literally why would it do that. Again, it takes like 200 coins - easily a full hour of gameplay, or slightly less of grinding - to roll once. Like I already have no control over this mechanic, why take away even more of this control?
Also don't actual gacha games allow you to at least usually roll multiple times at once? Like, I imagine a lot of my complaints about the gacha stuff would vanish if I could roll like, 3 or 4 characters at once. (Also if anime characters didn't have the naruto run animation).