If the horrible beam profile and tint doesn't bother you, and direct drive off of AAAs with a body far too big for cells of that little capacity, then by all means
Stupid thing is, there's no reason someone couldn't apply the same idea to a *decent* light. I actually have one, a 1xAAA Spotlight Shifter; does the "zoom" focus thing, but no weird artifacts. Hang a similar optic and sliding bezel in front of an XM-L2 and boost driver with a decent mode selection, put 18650 (or heck, even 2xAA so you can use NiMH) and forward clicky in the back, and you could have a pretty versatile light.
But I guess when Amazon/fleaBay/AliDirect/etc. are swamped with $5–$10 lights that, to most people "do the same thing," it's hard to justify selling for what it'd cost to build, unfortunately.