One major advantage of diving the Galapagos via a yacht tour is the fact that you get to combine a terrestrial tour with an underwater tour.
If you are traveling with those who are not avid divers, then they can enjoy the full tour of the visitor sites of the Galapagos Islands, and you can too. Most live-aboard dive boat tours have a mixed daily schedule, visiting two islands a day. After or before going to the trails on the islands, they often snorkel or dive. Sometimes the itineraries give an option: for those that are diving, it's under the water; for those that are land-lovers, to the island's visitor site. Likewise, some live-aboard tours can be specially chartered as diving only tours, or customized for a blend of tours.
Comfort is another major advantage of live-aboard diving. While on most dives, you get out of the water, take off equipment and sit on the boat for an hour or more until you get back to port. For those that choose a live-aboard diving, its only a short dingy ride to arrive at the boat, where your fresh water shower, dry comfy clothes and meals await you