I have collected many of those in my single life but people find it weird me collecting those stuff.. I like its cuteness and how good it makes me feel having those but I lost them all (i have it through going places and have something to remind me I've been there, a rocks for souvenir and I never thought it can be your pet). Maybe I'll have those rocks collected back since now its not just me who appreciate those and it's really not weird at all..
It is not weird at all to go out and search for interesting rocks and collect them. But, in my opinion, it is very weird to go to a store and buy a rock that has been marketed as a "pet".
That's some kind of weird though.. people's passion over a thing can sometimes lead the person to become the weirdest one.. maybe that's for some reason there good thing I'm not into buying rock pet but picking and collecting those for souvenir.