"Unimportant" roles

I feel like that there should be something along the lines of an "unimportant role." Essentially it is a kind of role used for basic identification or granting access to channels, but they don't affect the ability to use prune to remove these members.

Suppose someone is getting a role to get access to a certain channel. Doing this would prevent them from being pruned out from the server if they're inactive. If someone is a moderator or an admin, they would be an "important role," and would not be pruned out of the server because they have an "important role."