Not the first time I get to use them, but after that, sure. I might trade over all and merely evolve them to fill the pokedex, but its waaaay to restrictive to always have one of those types in your team.
I mean there is 15 other types!
I find it boring to see people use their starter and then add pokemon of the other starter types...like its not even that diverse, especially having both a Grass and Water pokemon... why not a Bug, Ghost, Fighting, Ground, Dark, Normal, Rock, Psy..you get the idea.
Probably because the most quality 3 stage designs are starters and a few others.