Purchases with points occupying ubercart
Yes you can use userpoints and userpoints ubercart. I did this in the past using drupal7. If you want to use drupal8, you need to check if the modules have been converted.


users can be allocated points by the admin person. the alternative is you have a product for purchasing points.
on checkout, points is presented as a payment option.
users can see their points balance and orders via their account page.


Another alternative is to use commerce_userpoints with its dependent modules (commerce, userpoints). But I believe this approach has a few outstanding bugs on the issues queue.