Was Tracey useful to the series?

No he was gay

Ha! No xD I didn't even know his name for the longest time he was so uselss

Lol i don't care if the character is useful or not -.- but he is a very nice character I think he is the most nicest guy on Pokemon. And for the useful part, YES HECK He was useful! He guided through the Orange Islands and WHO takes care of Ash's Pokemon troops huh? Tracey! And he is artistic which is a unique thing.
But when it comes to pushing the plot, No he did not had a good role there.

He was somewhat useful in the time at least only through the orange islands stage, bu in reality he was only a subsitute for brock because the creators thought brock was a racist during that era at the orange islands so to avoid problems they bought along tracey and brock came back when no one cared.