Hi Joelat

we have 10 approver licenses in our instance for the a selected group, and over 300 people managers that do not have any license.  All of them are able to approve via the Out of box approval email flow.

From what we had been told and seen, the approver license gives them access to Approval on the Self Service page, and access to the back end for easier use, but based on how we have our notification setup, it hasn't been an issue in the 3 years we have had it going