I use them only for crafting, as any other method of leveling a any crafting class will leave you brain dead. Seriously, it will leave you brain dead. That's not a joke.

It would be nice if they gave us different allowances for Trade, Field, Battle, and Guild. I agree that they probably want to limit it as it would make leveling to 50 too quick, but not because it would make gameplay too repetitive. I think they would be perfectly fine if all we did all day were Guild Leves, but if they ever allowed that, they would greatly reduce the reawards and they'd probably end up like Guildhests where you do them once and wonder why they're even there to begin with.