There is an upside and downside to everything, and that would include if you were a child forever. You'd never be given the opportunity to live out an adult life, or have abilities that an adult would. That being said, it all is thrown down into a discussion as to whether being a child for your entire life is worth missing adulthood.
Would you rather ride in a wagon, or drive a station wagon?
Overall, I think it is that thought that you could keep your childhood alive (the good parts, of course) is what makes it so intriguing. Imagine never growing older, being able to spend all day collecting pogs, beating your friends with Sock 'em Boppers, and watching KaBlam!, but take into consideration that the Kokiri were neglected of our childhood likings. What are we left with? A few friends, fairies, and a patch of woods. I'd imagine after a while, it'd become very tiresome.