Is a private yacht charter considered ultra-luxury travel?

Yes. A private crewed yacht charter is considered the most complete form of ultra-luxury travel, because it bundles every marker of the category into one booking. Private accommodation, a dedicated crew, a chef cooking to preference, and a route the guests control entirely. No resort matches the staff ratio: a typical crewed catamaran carries two to four crew for eight guests, and a superyacht can run one crew member per guest or better. The scenery moves too. Breakfast off St. Barts, lunch at anchor in a cove reachable only by boat, dinner somewhere else again. Villas and five-star suites deliver the staff. Only a yacht delivers the staff, the privacy, and a new coastline every day.