[Everything Barbossa is mentioning is nothing that Belle hasn't either thought of herself or been told by others. It's true that they are trapped there. And it's also true that the conveniences they receive are an oddity if they are truly only meant to be prisoners.]

A prison with conveniences is still better than one without. Although I believe they might also be a reward of sorts to repay us for the...other things we have to endure. [Like drafts and shifts.]