I kinda feel like heat would be wasted energy that could be used to ｇｒｏｗ

I think it’s more for the kind of people that do a couple of musical shows a day

I’ve lost my voice from singing as part of the crowd at a music gig before, I can totally imagine that being a problem that professional singers need to mitigate

A pretty dull one really:

Some singers use throat sprays to reduce irritation