It is recommended by Catalyst that you keep an admin account and a user account with moderation privileges. Separating your working account from the administrative account ensures that making changes to the structure of your project or major changes, must be a deliberate decision done on the administrative account; not something just done half handedly on your normal account.
To tie in with this; when you create your admin account or have an account with differing privileges, it is recommended you create the account with the syntax: youremail+accountprivileges@… For example an admin account would look like: youremail+admin@… This ensures a clear distinction between which account is which but it also allows your to receive mail for both account at a single email address.
The most common use for the start/stop instance role is for automated start up or shut down. You are able to add an automated user to the project that will only be able to perform start and stop commands on the system. This role is recommended over say the member role for security reasons. If the automated user’s account information was ever compromised or the automation changed in some way to try and make changes to the project outside start/stop commands, they would all fail.
This allows you to add users to your project, without giving them the ability to change or even see its contents. This role’s main purpose is for a user to be able to connect to your project then change their password and enable MFA. Then a moderator can give the user a more powerful role. This helps to ensure a higher level of security for your project.
Another practice of the auth only role is to partially expose containers or files from object storage to a user, without providing them access to the rest of your project. With restricted object storage access the user can be given read or write privileges for a specific container (or all containers) but still have no access to the rest of the project. For a more thorough guide on this please see Managing access.