When I see a bike with a wrapped exhaust, I'll immediately reduce my offer price by the cost of new exhaust system. The assumption one should make is that the pipe is going, going, and maybe already gone.
People put the stuff on to cover rust. It covers the rust, but it also increases the rate of oxidation, probably by an order of magnitude. There's nothing like maintained high temperature alternating with moisture retained against the surface to promote corrosion.
Some typical results when the noise suddenly gets loud and the wrap comes off:
-
https://www.reddit.com/r/dr650/comments/1cpohh1/exhaust_crack/ -
https://www.gomog.com/allmorgan/header2.jpg-
https://2.bp.blogspot.com/_hyWhE4IRh8k/TRrAo1e2_nI/AAAAAAAADmo/69EAgN8HKA4/s1600/brokeHeader.JPG
Me, I'd rather have an ugly pipe, than a pretty wrapped bundle of iron oxide chunks.
The purpose of the stuff was to insulate exhaust, thereby increasing exhaust temperature, thus lowering gas density, thus improving flow rate, performance at the cost of component longevity. I wish folks would stop using it as a cosmetic band aid.
Just my opinion.