I'm totally against betting points. The ranks are supposed to show the participants' skill in textual combat, which includes a variety of things - from knowledge of combat to analysis of your opponents strategy to forming one of your own - and allowing to bet points will skew the results, as a lucky bet based on simply the reputation of a fighter, and not an independent evaluation of their skill, could bring one higher up into the ranks than they have earned.

Betting anything else? Fine by me, that could actually be pretty fun.