I personally would never "gladly" place a concho, spikes, or the like on a guitar strap. But many makers do it all the time.. commenting "it's fine if you are careful" (I call BS)... I have one customer that is requesting Conchos. I am willing to do it as long as he understands that he takes responsibility for any damage to his guitar due to banging conchos against it.
The only hardware mine gets thusfar is a buckle and some Chicago screws and my buckle is on a strap that is glued and sewn to the main body of the strap. I do this for a couple reasons. 1. If the belt part gets worn and needs to be replaced It can be fairly easily to remove and replace. 2. The guitar and guitarist is protected from the buckle even on max length setting so no banging elbows or having a buckle rub on you. But that's just me... I own 15 guitars, 1 bass, 2 ukulele's and 2 mandolins.... and I would be horrified if I chipped or dinged the finish on any of them.