Is there a point in collecting all the flags in Assassin's Creed?

There are many collectable flags throughout the game of Assassin's Creed and every time one is collected, you get a progress indicator (e.g., 33 of 100). Is there any reason to collect these, other than bragging rights? I recall getting all available flags in one particular town and never saw any special reward or secret revealed.

The point is only to get the achievement. You don't unlock anything by collecting them.

There are 4 achievements associated with flags:

1. Keeper of the lions passant - Find all of Richard's flags in the Kingdom
2. Keeper of the creed - Find all flags in Masyaf
3. Keeper of the four gospels - Find all flags in Jerusalem
4. Keeper of the crescent - Find all flags in Damascus

The only usage for these flags is to have a save point in-game in case you die.