I define specific roles for each team. I don't particularly see a use for the Power or User roles. In fact, I find it annoying that "power" is added to app modify rights, by default. Are there any side effects of deleting these two roles to prevent their accidental use?
In general, most other roles will inherit the permissions and capabilities from the user role (some elevated roles would use power), so I would strongly advise against removing the user and power roles.
I specifically create new base roles to inherit from. For example, I create a base_user with no data access and some basic search capabilities. I also create a base_dev role with additional capabilities for editing dashboards and scheduling searches. My goal is to lock down access to "least required" by each team to meet audit guidelines. I am not seeing any inherited features of user or power in my other roles. Are there any hidden attributes that are inherited from user or power?