What a great idea!
I have no experience with lasers and clay. I did however spent 10+ years as a hobby potter almost exclusively doing stoneware slab building [I just sucked at throwing ] it seems logical that the heat of the laser will dry out the edges of the leather hard cut/etch.
I don’t know what the temp of a 40w laser is – but if I remember correctly stoneware vitrification starts to happen at about 2100F. And you’d have to hold at that temp for a while (and lets not forget the time to ramp up and down to that temp). While the laser is going to be passing over a tiny area fairly quickly. Possibly too fast to do anything more than bisque the edge (?).
@dan (or some other nice soul from GF) may be able to tell us the laser temp?
[[edit for clarification]]