You can if you like, I personally wouldn't say there is any benefit to it since you can just go and level the heck out of whatever class you are playing at the time with little down time in between for craft leveling. Fastest way in my opinion to level a craft is choose two in the same city and use the leve that gives the most EXP that way when you end up having to port out of the city you will be in the same place for both and level two at a time. But that is for the crazies like me that like to power level stuff fast. As for end game perks with a craft, they are very minimal, people use it to get crafted gear and such for starting the raid/dungeon play but imo you can live without doing that. Personally I use crafting just for profit, and knowing what to make and what crafts is important on your decision of what to level.