I knew someone would say that.
What I mean by “unnecessary” is that, on my priority list, “a movie set in a different era with different characters” or “a movie set in the OT era but with themes and characters that are in no way connectd to the OT” is much higher than “let’s have a movie about a younger Han Solo and Chewbacca, and, oh, let’s add some pointless fanservice like how Han won the Falcon”. And that isn’t even the worst bit (I have read a certain godawful spoiler, but, it’s a spoiler after all).