I think it helps more in your head than in reality. I’ve got a really good spot for bow hunting but the topography makes it very prone to swirling winds. You can literally get 4 bursts of wind and every one is from a different direction. Bought one with that set up in mind but after two seasons I can’t say that I’ve noticed it making any kind of actual difference in that or any set up I have. Plus when there isn’t much of a wind to make background noise the thing sounds really loud up there above your head. The deer I shot last fall circled downwind before coming in and didn’t scent me without using it, was also a clear morning so had rising thermals in my favor too.
Probably the most usefullness it has for me is ill run it in a small room with my clothes before hunting for an hour or so, seems to help keep them not smelly, but maybe just in my head there too.