I mean, considering most of my characters are incredibly unrealistic and quite a few have some unnatural colors on them, I'd be a hypocrite to say no. I don't like full on neon characters (like the types often seen used for trolling and such), but I do like having neutral colored characters with unrealistic colored markings (like my character Negative with a brown base and green markings, or Ryjal with a grey base and blue markings). And occasionally I'll have the character with an unrealistic base color as well. And honestly, there's only so much originality when you stick strictly to realistic colors and markings, especially within Feralheart.
I see nothing wrong with sparkle characters, just as long as you don't make the colors... too bright. Make your character how you want to make them! I'm not gonna go around being the Character Police, lol. If you want to make your character realistic, go for it! If you want to make them unrealistic, go for it! Character designs can tell you quite a lot about a person, and I like seeing how different people use different colors to create their characters. So yes, I do like sparkle dogs.