What exactly does the approver_user role grant you?

Other than granting you access to the My Approvals Module, what specifically does this role do, other than cost you money? I don't see any ACLs or anything that specifically require this role. Furthermore, if someone is an approver, and that's the only role they have, why can't they have a read only view of the record they are approving? It seems like this role wasn't fully thought out, what am I missing?

And please don't respond with a cut and paste of the vague base role description. I'm looking for a more detailed response from people in the know.

Thanks