I would say that an incident meter is exceptionally useful when the subject is (mostly) frontally lit. I would use them almost exclusively for studio portrait type work, in which I would make sure to shield the meter from either a hair light or "kicker" (from behind). This would be with a "dome" on the meter. If you were doing flat artwork you would prefer to use a flat diffuser which is sensitive to the same angular fall-off as the painting, etc., and which would not be able to "see" lights from behind the artwork.
When you are in places that are NOT frontally lit then your judgment comes into play.
For tricky outdoor scenes (ie not frontally lit) I would prefer a reflective meter. If I HAD to use an incident meter for this... I'd probably take readings in the most shaded area, making "estimates" (wild guesses) as to what it takes to get a little shadow detail. Then perhaps a reading in the lighter areas to see if I can find a happy medium, or whatever. It might be worthwhile to spend a couple hours with both meters - your incident AND spot - seeing if you can correlate your incident readings to the spot readings (which I would take to be more "correct").
People who live by their incident meters have worked out (according to literature) methods of metering just about anything, but I don't really trust 'em IF THE SUBJECT IS NOT FRONTALLY LIT.
Using a flash/incidental light meter , in a studio or out allows you to meter all light sources falling on your subject, no just the space between the front of the lens to the subject.
Either with flash, natural or a combo of both, knowing what the scene looks like in the whole, will allow you to tune both your camera and the scene, with all the direct lighting that is falling on your intended shot.
As you move around your topic, in this case, meter with a hand or card excluding all but one point of direct light, at a time.
Make good notes, mental or paper, with the meter's dome, pointed to the source you should easily see it in the dome as a highlight.
Decide your main light source ss/fs and then adjust the scene's other light sources as needed.
Scrims, umbrellas, cards, additional light from lights or reflectors, or darkening a side with a black card, cloth or wall, say for example, reducing light bouncing back in the far side of a face, all work, you just need to learn about and employ these methods, for your desired final photograph.
Pointing meter at the camera works up to a point, but you can do more to get the best analog negative you can with simple methods.
IMO.