I'm watching a riveting movie. I have no desire to get up or do anything else. Good thing that because I'm on a transatlantic flight.
Intuitively, I think I would be better off if I were watching that movie at home and could get up, walk around or stop the movie and take it up again later even if I didn't want to do any of those things. Factor out typical differences in the comfort and legroom of economy class seating and easy chairs in the average living room–put me in business class if you'd like. It still seems that the mere possibilities I enjoy in the comfort of my home contribute to well-being.
And it doesn't seem to me that I just want possibilities as a hedge against future contingencies. I have (really) on some occasions paid (around $20) for an aisle seat on a plane so that I could have the mere possibility of getting up without a hassle. And when, on those occasions, I didn't in fact want to get up but cheerfully sat through the entire flight I still deplaned satisfied that it was money well spent.
Mere possibilities don't figure in experience so hedonists have a quick answer. But if we understand well-being as preference satisfaction we note that we can be made better off by states that don't figure in experience. So…why not by states that obtain at other possible worlds?