Are large space ships possible/worth it for humanity? If we could build moon sized ships capable of carrying hundreds of thousands of workers would it be worth it? Keeping in mind the progres of technology over time would humans settling on an alien world 800 years from now be traveling in advanced rockets or some sort of super structure that would act as a base?

Basically would future technology yield bigger space ships? and would it be better to just use rockets? Basically I'm trying to figure out what a huge space ship would look like/if it would even be something humanity would make.