One problem with stud conversions is that they then normally change what size wrench / socket you need for the car.
IIRC our stock wheel bolts are 17mm heads. I've never seen an M14 stud kit that comes with a 17mm nut, because it couldn't fit over the M14 stud very well / no material would be left on the nut. So then you're changing to a 19mm socket. This on its own isn't a big deal, but many wheel designs can be tight around the holes, and a 17mm "protecta" socket fits... but a 19mm won't.
So then you're stuck trying to find a thin-wall 19mm socket (or pulling the protective sleeve off of yours) and hoping you don't bang up the wheels. Or, you then have to search for a weird nut (e.g. McGard, Gorilla) that uses a spline drive or some other funky "key" that will also act as a super-thin-wall socket.
All of this isn't
hard per se, but it's an additional pain in the ass that people who have never dealt with a stud conversion would never know about until someone mentions it.
