Roll in shower rooms actually have a shower that you could roll right into with a rolling shower chair.
There are wheelchair accessible rooms with tubs with grab bars - some people with disabilities prefer to have a tub to soak in. Those will be labeled as wheelchair accessible with tub.
The wheelchair accessible with transfer shower can‘t be rolled into. They usually have a shower that is entered from the short side with a fold down bench. You can push a wheelchair next to the bench, then transfer from wheelchair to bench for the shower.
This is a link to an accessibility review of Coronado Springs
It includes a picture of the transfer shower