Why is cruise tourism both a means of transportation for tourists and a tourist destination?

Historically, cruise ships have often been used as a means of transportation to transport people from one continent to another, as well as soldiers or goods. But now, this function is gradually weakening, and it has gradually become a destination for entertainment and tourism. Modern cruise ships are like a small community, which integrates catering, guest rooms, leisure, entertainment, casinos, swimming pools and theaters. In addition, service also reflects the attraction of a community. At present, it is not enough to entertain only on the cruise, so there will be corresponding port cities to provide ground tourism services, which is why cruise tourism is both a means of transportation and a tourist destination.