I hot stamped some napkins using handset type (probably monotype), and
discovered some rounding of the edges. Later I stamped some Christmas
cards using a Ludlow slug. I did not notice any deterioration of the
type, but it was a short run (25-50).
I would certainly not use any of my expensive handset type for hot
stamping. Ludlow has a lot of different typefaces, and if it gets
damaged, it is easy to cast several duplicates. To me that would be
the highly preferred way to go for hot stampling.