This is all true but it also is true that MTE was in part built to accelerate address sanitizer.

Kostya/et al who pushed for and designed the extension, was trying to accelerate address sanitizer so it could be on all the time. Among other things.

In fact, most presentations presented it literally as a way to do hardware accelerated ASAN (again, among other things), so the post you responded to is correct in that sense.

(I was there at the time, helping him figure out how to push for it)