The major benefit I can see is that if you are looking at a fragile ceramic PCB you don't want the operator holding it, so maybe you can make some kinda limited range of motion jig to put it up on (i assume you still wanna tilt it a little bit), but i don't know if there is good reason not to do the same with a video scope.
do you think the 3d vision makes it easier to see since your brain gets all the info at once, rather then trying to fuss with it in 2d? since its giving you more information in any one time. I never used a mantis, only a eyepiece one, which I find downright irritating to use.