1) Most experienced players will either use a roller or manually type 'n' over and over again to get maximum or close to maximum stats.

2) A first-time player will be confused by the roller, and go by old roleplaying knowledge and think that 15 is a good stat to have.

Why not a point system?:
- It would allow much greater determination of stats based upon the player's desired role for the character. (for example, if a player wanted his necromancer to be frail because of some magical rigors or whatever he could set his constitution to a low value). If you notice, even characters roleplayed as unintelligent will still have the maximum intelligence for the race. I blame this partially on the rolling system, though it's also a byproduct of player mindset.

- You could set the given points so that no one could be rolled with maximum stats, or however you wish based on the power level desired.

- Monstrous time-saver. No more spending hours at the roller trying to get those perfect stats, and no more advantages gained by players who manage to acquire a good stat roller.

There really are no advantages to the rolling system, at least none that I can see.