The Summit does not have the "ship within a ship" concept that Yacht Club has. I don't think X got that right until the Ascent. BUT Summit is not as big, nor does it carry as many passengers as MSC.
Having been in Yacht Club, we avoid going "OUT THERE" due to the crowds. We went out for the Diamond Party and walked around while the ship was in port and the crowds were off the ship. Other than that, we had our own pool, bar, buffet, dining room, and entertainment. If you want anything from the buffet, the Bulters will get it for you.