My boss got me one for working inside control cabinets. As you usually have to have to power cut when poking around in a cabinet, lighting has to be supplied externally.

They could theoretically be decent for some car work where the body of the car shades everything.

They're better in idea than reality. 6/10

Also think of them as a supplement to a headlamp. Since your hands frequently shade what you're actually touching, these help supplement light right on the region of a hand shadow.