Thanks for all the perspectives. I have always hesitated to do this, even at home, for the reason MomOTwins mentioned, but recently I read about people doing "Dessert Hops" around the monorail resorts and Epcot similar to bar hopping. I am not interested in that, but just one dessert, later in the evening after the dinner rush. I rarely eat dessert with my meal, but there are a few that sound very tempting that I would like to try on their own. I may try doing a walk in: if there are tables available, I wouldn't feel as if I were taking a table that might have gotten a full dinner order.
As for the lounges, I just feel there is an expectation--even at Disney--especially late in the evening, that a lounge is really a bar and the purpose is to go there and drink, rather than eat. I would feel a little uncomfortable with that.