Doesn't Teflon degrade due to the high Temps? I really don't know that much about it, but it's just the opposite with cast iron seasoning: heat hardens.
We were talking about scrubbing.
For heating, lots of carcinogenic compounds are released during the process of seasoning, and I don't see why the same wouldn't continue to happen at high heats afterwards(happy to be corrected). Hardening and releasing dangerous compounds aren't mutually exclusive.