I know that for pit bulls, they have powerful tails. None of my dogs have had docked tails, but my furniture has suffered from it. Dented refrigerator, paint chipped off the walls, and my first dog even broke a mirror with her tail; only the furniture has been damaged, I've never experienced any broken or split tails. Some may do it for looks, but it's practical for more than just health reasons. Especially if you live in an apartment and you want to get your security deposit back.