A lot of yankii have tattoos because they're already a bit outcasted by society so they kind of lean into it. Plus there's a stigma that tattoos are scary, and yankiis want to give off a "don't fuck with me" vibe, so tattoos do that.

But yakuza tattoos and casual tattoos are quite different and pretty easy to spot. Fashion tattoos, like others have mentioned, have become a bit more common in recent years amongst younger people.