I see a bunch of pro and con arguments here. Removing the "let's not make this a porn movie" style responses, I don't actually have a problem with the idea.
Romance options aside, I find that I have a hard time raising approval ratings for companions who aren't regular party members. If they don't head out with me every time, their approval rating of the MC tend to be pretty neutral for my games. And maybe that's fair. But it means that either I have to break emersion for myself by constantly 'going back to camp to switch companions', or facing the late game dilemma of being low in certain companions' estimations problem. This might be a decent compromise.
A better solution might be to have positive/negative modifiers from in game decisions actually translate to party members in camp, the same way that certain dialogue/plot points do.