What's those reasons?
1. Dan's reason as I understand it: If you have high balances they can shut down your account and he doesn't want to put those points into jeopardy.
2. My reason: these points are related to business accounts and in addition to those points on my accounts I don't want to do anything that could get the actual cards/lines of credit closed. For me these points are just a fun by product of running my actual business, which is a much bigger priority than making a few bucks from selling points.
3. It's against the stated rules so for many that is enough on its own.