You sure can!
All cards that offer this feature have a "Points" tab available in your card screen, in addition to the "Card" and "Notes" tab. Before you can access your points via Stocard, please make sure that your card account has already been activated on the respective card provider's homepage. The login credentials you choose there will then also be your login credentials to access these particular points account via Stocard.
If your card does not show a "Points" tab, this means that this feature is not available for this particular card yet. However, please always feel free to send us your suggestions for cards where you would like to see your points balance to email@example.com and we will try to make this possible in the future.