Unlike GTJ who appears to be a good historian but not a current Bay Area resident, my perspective comes from being a San Francisco native who still resides in the Bay Area. I regularly ride BART both to the city for activities as well as to both SFO and OAK. We have taken it for cruises on multiple occasions. It will be fine for your SFO to the hotel jaunt. It serves no purpose for travel within the city itself. That is best served by Muni. However, do not use the F-line to get to the cruise port. It currently runs a variety of historic trollies and they do not do well with luggage. When we cruise we take BART to the Embarcadero station and then walk a flat mile to pier 27. In your case, departing from the Parc55 it would be much better to go the Uber/Lyft route, or a taxi.