How does PVP work?

Hello folks,

Since players have started to experiment with PVP, I am curious about the present system. How does it actually work?

From what I've read, teams are basic dungeon small teams: 1 tank, 1 healer and 2 damage dealers. Two teams are then set into a death match arena and will fight until one team is down (or the time limit is reached).

Then, how does it work?
I'm assuming a damage dealer's job is to kill the healer, then the damage dealers and finally the tank.
I'm assuming a healer's job is to maintain the party alive.

What is the tank's job? Be annoying? From what I read, you need to target an ally to give a damage reduction buff (which means to stop attacking) and since the reduced cooldown is 3 minutes and last 8 seconds (so 2 attacks per enemies), I'm assuming this ability is more of an "oh shit" button rather than a actual tool. So if I'm not mistaken, the tank is just there to be hard to kill, low on damage output and therefore just annoying. If that's truly the case, that sounds boring.

For the progression, I'm assuming it's the usual:
1. Enter PVP.
2. Win/Lose.
3. Get points (more points given to winners).
4. Use points on character skills and gear.
5. Get more powerful against enemies with less character skills/gear than you.
6. Get all character skills/top gear, utterly destroy enemies with no gear and show what you are made off against geared opponents.

Is there any rewards that are useful in the rest of the game? Like gil rewards or experience points? Or is it purely PVP rewards?

If the system described above is actually used, how much more powerful is a character with top gear VS a character with entry gear? Is it very long to reach decent gear to avoid being crushed by more geared characters?

Thanks,
Lloyd Shade