Is splat dye really THAT bad?

Ive heard it damages your hair and like never comes out but is that really an issue? I’ve been using arctic fox purple mixed with blue to get an actual deep violet and it’s worked out great so far... except the fact that I can’t really shampoo my hair if I want the dye to stay. So wouldn’t the splat dye be better in that sense, or is that not how it works. And damaging my hair isn’t really an issue for me because it’s already kind of damaged, unless it’s gonna make my hair feel like dry grass then I’m out. Just trying to figure out if it’s a good idea to try it out or not, thanks!