It isn't perfect, but the idea of a convertible grav deck that doesn't require complete reconfiguration of its interior if a ship is under thrust isn't a bad one. I think it would be worth a modest amount of additional tonnage, and combined with the loss of floor space, it would be suboptimal in a lot of ways. And to be clear, I'm not asking about any other aspect of the ship (place in canon, docking collars, etc.). HBS had a novel idea for a grav deck and thankfully shared it with us.