That is like saying I visit cities in the world but never leave the hotel. They all look alike. If all you do is get off the boat, go into town, visit Diamonds International, then all the islands look alike. If your friends went to the BVIs and did not go to the Baths then they really missed a unique beach experience.

Some islands have good beaches, others have good snorkeling, and others have historical things to see. Excursions from the boat are good. Trips from the locals just out of the pier are usually cheaper and fun. There is only one port (and maybe only one city) that I know of where you can get a private city tour in a 1959 convertible. And that does not cover river cruises that take you to exotic places that are nearly impossible to get to on land,