They are great for skilling up summoning magic if you do not have other avatars. Always keep your summoning magic as high as possible. I keep mine capped.
I cast air spirit and just left it for a few moments and it kindly cast protect on me. 12/smn/whm. I look forward to finding out what the other spirits can do
The air spirit is stupid! I freaking wasted 6k on it because i thought it might be useful to fight with. Im freaking poor and im a noob i know, but i was pissed that i wasted all my money on something that costs more mp and is 10x crappier than carbunkle. I guess its all part of my smn collection but its gay, I would rather have elton john fight by my side than this piece of crap because it would make me feel more straight. Honestly, i dont even understand how a sphere with a piece of grass spinning around it could even hurt something? Oh yeah, thats right, it pretty much cant, thats right... So anyway my point is that if your poor and have to save up for 3 days just to get 6k dont waste your money on a stupid air spirit because its stupid.
Wind->Earth If you solo/fight worms you may choose this over carby. Even though it has higher cost, It tends to hold it's own vrs Maze makers and other worm type mobs. Granted both carby and wind element die pretty quick but the wind elemental can do far more dmg to the mob during it's life span. and someday you will have garuda =)
Its not that stupid. All spirits can cast anciant magic. Air spirit can cast Tornado but only at the level that black mages can cast it (so somewhere between 50 and 60)
not only that its a very quick cast like all elementals and good for throwing it out and sprinting for the zone.
Admittidly its a bit rubbish, it doesnt do that much and its a bit costly on the MP but you wont regret it while you run for the zone