So, you go downstairs to the Duel Arena, check out what is required to join each set. Discover it is something stupid, like No Armour and Melee only.
So once you've got your inventory sorted for that match, you join, only to discover that there is a 10 minute wait time, and you have absolutely nothing to do in that time, since you don't know who you are facing.
After the painfully-long wait, you finally get into a waiting room for a pointless split-second, then shoved into arena, almost certainly facing a very high level with Godsword etc.
If you somehow do manage to beat them, you WILL get killed in the next round, wasting food and potions for shit xp. This minigame is pointless except to those 120+ combat with the best equip money can buy.
Now, about your "Tournament Points." You start with 1600+ Your Combat Level, so high levels have an instant advantage. Beating 1 opponent earns you no xp, beating 2 earns you about 4. Losing loses you about 12. Just breaking even is hard.
High levels: It'll be piss easy, just go and own.
The rest of us: It's useless.