I understand.
Never had a tube amp go on me. Not once.
Not a tube, not a component...not from heat or overuse. Had plenty damaged from dumbasses dropping my shit.
I am not saying it affects the sound...but it definitely affects feel. IMO. From my experience.
We all know an amp runs a certain way live, so I just try to get the amp there while practicing or recording....so I just did it that way.
Something I started doing during winter shed practices in northern Michigan....and in cold venues. Worked.
To each their own. Just saw your fan post ...and thought it funny how I did the opposite.
Also, I don't do it during hot and humid weather...just when chilly. Mostly to have an even and consistent heat....for predictable feel.