I've been offered the use a of a friend's apartment "cheap", but by the time we've added on flights, with luggage, and airport transfers, it's actually cheaper to go to the same report on an AI package. We just want a few lazy days out of season.
So, even if we don't use any of the AI facilities or food, it's still cheaper, and the liklihood is we'd use it for some drinks and icecreams etc, even if we didn't eat in the restaurants.
But (and maybe it's the snob in me), I can't help thinking the other option would make for a better holiday, despite less good facilities. Friend's apartment is in a small block with a small pool and close to bars and restaurants used by locals. The AI place has multiple pools and restaurants, plus fairly easy access to the other restaurants. It is a little bit out of town, but closer to the beach.