Default roles throughout most of the game, and it's also a more efficient way of using the CP cos the accessories/atb slots are typically within the default roles. It makes less 'economic sense' to spread your CP thin especially when it's harder to obtain massive amounts in the earlier stages of the game. It was only after I maxed out my stage 9 crystarium and had a meagre 100k or so left of extra CP points that I let them venture into somewhere else. WHich really didn't get them very far except a few basic abilities.