It depends on how we define "worse."
A breaking change causes a full-stop to a service.
An intentional slowdown lets the service continue to operate at degraded performance.
I concur that it's less clear for debugging purposes (although any reasonable debugging infrastructure should allow you to break and see what function you're in when the program hangs; definitely not as clear as the program crashing because the called function is gone, however).
A breaking change in a dependency doesn’t cause a full-stop to a service at all. The old version continues to work. Making subtly harmful changes so that new broken versions sneak in is just a bad idea and totally unnecessary.