Originally Posted by
TiHabanero
This is my experience as a shop mechanic for several decades. The replaceable Der hangers weaken over time. I don't know exactly why, but they come through often enough out of alignment for me to believe this does happen. I have not seen a titanium frame with an integrated hanger go out of alignment or break off in a mishap.
They are somewhat designed to fail the idea is those break and save your nice derailleur and your frame. I would much rather spend 20-40 bucks on a hanger than 100-5000 on a new frame and 40-500 on a new derailleur (obviously depending on what derailleur or frame you have an such)