What geographic challenges led to the use of island hopping?

The term island hopping was used during WWII when the US and its allied forces were going from island to island trying to regain and push out the Japanese forces in the islands from Guam, Tarawa, Guadalcanal, Palua, and others, including Okinawa. Most of the tiny atolls were bombed, however, the only way to take over them was to land forces and literally flush out the Japanese soldiers by fire. Chuuk in Micronesia was believed to be very difficult to land troops and it would take a great amount of forces to land, so the US and its allies blockaded the entire lagoon, starving the Japanese. That is one of the island hopping terms I have heard. Marine are notorious for these beach landings, many of their hero's were made in the island hopping campaign.