For their size those are very impressive, I'd be quite concerned about cooling them but there must be applications where their form factor would be a game changer.

Looks like the wrong kind of thing? Those seem to be high speed drone motors.

Am thinking they'd not have enough torque, unless you gear them pretty high.

Further down the page, they explicitly call out CNC applications. ("IQ motors are smoother, quieter, and more efficient than stepper motors, and they will never skip a step or get lost.")

They are basically a stepper motor from the application's point of view, but with some of the advantages of a servo, as far as I can tell.

(No affiliation, just curious if these guys are onto something useful.)

Just judging by the torque specs and comparing to a nema23 stepper, seems like it needs an order of magnitude more torque to compare. Note that in the comparison chart they compare to a nema11, which is tiny compared to the steppers used in most hobby cncs.