how permission scheme defaults are generated? - JIRA Service Desk

[vrgl2]

When creating a new project in JIRA Service Desk, a new permission scheme is generated, 

assigning a bunch of permission to security role Service desk customer - portal access

Some of them doesn't seem to hold any value for the portal customer (Schedule Issues, Delete Issues, Link Issues, Modify Reporter, etc) since the customer is not really able to perform these actions through the portal.

For example, if the Due Date field is not present in the Request type on portal, and the role Service desk customer - portal access is removed from the "Schedule Issues" permission, Jira will report a non-critical permission error, saying that: 

The Service Desk Customer - Portal Access security type should be assigned to:

• Schedule Issues

Same goes if the role is removed from other permissions: 

• Modify Reporter
• Schedule Issues
• Assign Issues

Question is: Why is this role assigned several permissions if they are not actually useful for it?