if you have crew, you also have crew supporting things such as: kitchens, sleeping areas, gathering areas, rescue boats, toilets, etc. All of those could add

if you have crew, you also have crew supporting things such as: kitchens, sleeping areas, gathering areas, rescue boats, toilets, etc. All of those could add more space for cargo. I also imagine not having to load up food, supplies, etc would also save time/effort. You could also go as slow as you want (saving fuel) depending on your cargo..