Why not?
It's one of the few ways to actually bring back a measure of fairness again. Sure, you have your crazy spells that could be "I win" buttons....but you take a risk by using them just as much as anyone else takes a risk by using anything else.
What is so harmful about taking away the fact that magic uniquely acts as a "get out of jail free" card? I genuinely don't understand what the issue is. Heck, it's not even like this is something PbtA/FitD/etc. introduced. "Casting spells is dangerous!" is a mechanic that's been around for easily 30+ years, and it's all the rage in the OSR scene. I personally don't care for the typical OSR expression thereof ("spells are great, but one bad roll and you die horribly...if you're lucky"), mostly because it feels like turning magic into a "screw you for even trying" process. But having spells be able to blow up in your face some of the time if you screwed them up? I genuinely don't see how that's a problem.
Obviously, 5e specifically it would require playtesting, perhaps even extensive playtesting, but I don't see any reason why it should fail in practice, let alone in principle.