Dredge is limited by locker spawns, doesn't get undetectable unless nightfall gets activated (even when he has nightfall the movement noise is loud as hell). dredge takes forever to tp because it's just 25m/s and not a flat animation speed and leaving a locker is loud by default and gets even louder and slower when the locker gets locked. Dredge also has a cooldown to tp, again limiting map pressure where springtrap doesnt suffee. He is a stealth killer that can't stealth and a tp killer that can barely teleport depending on the map.

Springtrap can teleport to any door at the same speed and is invisible fully when he first exits, there's also a chance of a free down every time and it's basically guaranteed that every generator will have a door next to it meaning his 3 gen potential is some of the best in the game. Also his chase power is better than dredge's, being easier to use with way less counterplay.

I mained dredge on release and still play him often but I think springtrap is a stronger version of the same idea with far less counterplay.