organizational custom roles

Summary:

Hi Everyone,

I'm going through the creating the custom roles, I've created the custom role successfully, but I want to understand this deeper, where type, indicated role or organizationRole, I understand the organizationalRole, what is "role", How this will be useful, I've created role, where I can use this role? I'm not able to see this in any organization, how this will useful.

I've a use case where, I would like to create a role with only accessright as

 "repositoryId": "ora.viewCatalog"

So that user just can login, view the items, but he will not able add items to cart and place order.