The primary use of flight is for PvP, you'll fly more in the Abyss during PvP than anywhere else in the game.
However, I will suggest one thing right now. If you are having doubts now, then I would suggest that you dont continue. I dont say that to be mean, its just that in my experience if someone isnt really into a game then they will subsconciously "see" more and more faults and will ultimately just end up disliking the game anyway.
As I've maintained all along, Aion (like any game) isnt for everyone. Theres nothing wrong with not feeling the game, it just means that it and you arent suited. No harm in that. Thing is, nobody can convince you to play, either you like it and have fun, or you dont. Ultimately if you keep playing when you dont really want to, based upon someones attempt to convince you, then the chances are it will just grind away at you until you end up feeling venomous towards the game.