It seems to work well on normal denim. I tried my daughter’s thin denim stretchy jeans. The etch looked good but disintigrated as soon as she put them on.
The local leather store has a bin with scraps for $5/pound. Lot’s of unique embossing and colors. I grabbed a bunch. Do test engraves. I guestimated and the engrave is a hair too deep. I also reduced the size of the leather R 1%. That was either unnecesary or too much. There is a very slight gap between the leather and the wood. More testing needed.