One of Star Wars' greatest strengths is also the source of its greatest problems: fan expectations. Every fan who forswears the entire universe for one new film or another, just can't tear themselves away from the saga. For better or worse, each installment does try to service those fans by including connective tissue to the past while telling its own story. The Force ghost of Anakin Skywalker watching over Sabine and Ahsoka in the Season 1 finale of that series isn't just fan service. It's an important capstone on the story the show wanted to tell.
Source：https://www.cbr.com/last-shot-ahsoka-finale-not-fan-service/
