Is there any possibility to use this plugin as kind of a voting system for entries?
Something like user A posted and entry, and user B and user C can down- or upvote (once) on that entry resulting in user A receiving or losing points. I.e. any user can post an entry and all others (including himself) can up- or downvote on that entry taking influence on the points of the user who posted.
I would assume because it is event-driven this won't be possible out of the box but maybe I got that wrong.

Is there any way to group or tag points, so I can display different user badges based on how the points were earned ?

Is it possible to buy credits with commerce or stripe? Coule be an awesome feature.

Manually assign x points to user in Control Panel.

I think this would be great for a project I was about to start where I can use these as points as "credits" in conjunction with Charge for Craft in that people could purchase credits to post entries and then we could subtract the credits once they have posted their entry.

It would be great to be able to subtract points on certain uses... I guess another way around this might be to tally up their points and compare it to how many entries they already have, and the remaining number would be their remaining number of credits.