So are battle ranks only a presentation of how much you have played on that character or do higher battle ranks also reward you with anything else other than titles/decals? If that's all they give you then it seems to me that buying EXP boosts are useless (to me at least. I don't give a **** about decals/titles they don't help me in any way). Do you get certs when you level up? Do you get more certs the higher your rank?
It allows comparison of digital penises, so that two people can learn, empirically, which one of them is more masculine and qualified to mate. Or, at least, that's how it's used in practice.
Higher ranks kill lower ranks, due to the improvements they can get from having more Certs earned than you. It will also show dedication to the game, and most likely they have spent money on worthless digital weapons that give them an edge over you. That being said, a BR1 can kill a BR30. I know. It happens to me from time to time.
Certs come with XP and have nothing to do with Battle Ranks. BR comes from Planetside 1 where each lvl would grant you another Certification Point to use on skills and at key levels an cybernetic implant. Only each BR would you get that cert point to use. Sadly BR serves no purpose in PS2.
You get 1 CP (certification point) for every 250 XP you acquire, so Experience Boosts are very useful.