[mft_]

You're right that such things already exist; I think it would offer two incremental improvements:

* for wood, faster and/or thicker cutting, vs. existing CNC laser cutters

* for sheet metal, neater/cleaner cutting (i.e. cleaner cuts, higher tolerances, less subsequent prep-work needed) perhaps in a smaller neater machine, vs. existing CNC plasma cutters.

Especially within the context of a CNC machine, I wouldn't be overly concerned about safety - all of the more powerful CNC laser cutters I'm aware of already come with an exclosure - both for laser safety, and to constrain smoke (before it's vented safely).