I don't think there's a positive side to Tingle
For me, Tingle represents a time when Zelda turned into dribble. I suppose it's different for people who actually enjoyed Majora's Mask though.
Well I think you deserve a smack to the head for not enjoying Majora's Mask... no offence Mammy
I don't have an issue with Tingle appearing in Zelda games, because I guess at the same time there a lot of awesome characters too... Tingle is just, the epitome of, something awful. I mean in Majora's Mask you had cool characters like Skull Kid, Darmani, Mikau and Kafei, fun, playful characters like the Bombers, Romani and the Deku Princess, beautifully-composed characters like Anju, Cremia and Lulu, and quirky, weird, mysterious characters like the Deku Butler, Kamaro and Igos du Ikana. And then you have Tingle. You don't have to put up with him for the whole adventure, he's just kind of... there. If he was there in larger doses, he'd be really friggin' annoying.
Anyway, I think Tingle is a character who was just better received in Japan, and the Tingle DS games were meant to be distributed in Japan. That's pretty much why they weren't released internationally. So threads like this on Zelda forums like this wouldn't be made.