Planes don't just catch fire in the air on a routine basis
No, they don't. But if this discussion serves to send at least some of the 'nylon pilot shirt plus hi-viz vest' brigade thinking and realizing that they are effectively wearing a shrink-wrap, then this is a good thing.
I don't know if you've ever seen a serious burn victim close-up. I have - trust me, it's not a pretty sight.