There aren't really any standardizations or best practices around points, but I can provide a couple viable solutions.
If you don't want to include points at all, only include the actual payments in the product string, so $0.00 is recorded for purchases using points. Instead, count points in a numeric/currency event (depending on how you want to track points). If you wanted to see an aggregated total, you could create a calculated metric that added the two together.
A similar option would be to record everything, then include an additional numeric/currency event that collects point value for purchased products. Then in Analytics you could create a calculated metric that subtracts points from overall revenue to get only direct purchase income.
Which one you go with will depend on what your requirements are for tracking revenue, as well as how flexible your platform is for collecting this kind of data.