Any kind of test environment closer to home is helpful.

Notably the Starship system takes at least 12x the launches to put a payload into deep space than it takes to put a payload into LEO.

With those economics it might sense to build large structures in LEO, such as a flashy space hotel or a simulated lunar or martian environment patterned after a very small O'Neill colony -- recent research seems to show people can tolerate a higher rotation rate than O'Neill thought so a small Bernal sphere made entirely from terrestrial materials looks possible.