Free models usually has viruses in them which tends to ruin your game. I remember when I was building with my little brother in team create he used a free model that had a virus which if a person joins your game they will get teleported to a different game and after deleting all the models that were not mine the virus was still active for some reason.
I’ve seen a few top games use free models but they only use the ones made from roblox or recommended by roblox.