There is a difference between using models (CGI or physical) to accomplish shots which can not be done with sets and costumes and just doing it because you can.

The Cloud City and Death Star corridors look more realistic than most of those in the Jedi Temple because they are actually there and lit by real light (all be it stage directed which is an art in itself). The director can chose to move the actor from one side to another based on what they can see through the lens.

With a virtual set you have to distort the surroundings to fit in with the few real world elements you have which may save money but doesn't look natural (even in a fantastic universe sense).

At least a physical model is a real object which is hit by real light.

CGI is getting better (already many of the TPM effects look more dated than the ROTS ones and SE often stick out like a sore thumb) but the difference is still noticable.