I don't think it's valid anymore to count TAS as "not canon," given that Roddenberry's '89 memo decanonizing TAS has been routinely ignored for a long time now. Back when GR was alive, there was some validity to his attitude that TAS and the Harve Bennett movies were partly or entirely non-canonical, since he, the creator of the series, didn't produce them personally (and the same might've gone for TOS's third season to an extent). But by now, Trek canon has grown far beyond "shows produced by Roddenberry" or even "shows produced solely by Desilu/Paramount" (since the Abrams movies, like TAS, are produced by an outside company in partnership with Paramount). So I don't think there's any legitimate reason to consider TAS as not being part of the canon. It's onscreen material, it was authorized and co-produced by Paramount, it had the participation of the original cast, and it's been at least indirectly referenced in multiple other canonical works. It's even covered on the "canon-only" sites StarTrek.com and Memory Alpha. The only basis for not
counting it as canon is Roddenberry's memo from over two decades ago, but that memo has been disregarded since his death, and he also considered some of the movies to be non-canonical as well, so his opinions clearly are no longer binding.