mgr/dashboard: Block-Manager role does not allow listing existing RBD pools
A user provisioned with Block-manager role only, when creating a new Image is not offered with the pool selection drop-down menu. While it still allows for manual entry of the RBD pool (and it eventually creates the image), for the sake of user experience, the behaviour should be similar to the one provided for other roles.
The only thing to take into account here is whether Pool read access could expose sensitive to RBD/Block managers. My guess is no, but let's see what others have to say.