Conversely, TOS stand alone episodes limit development of the characters and after a while, the episodes begin to look repetitive.The trouble with Buffy's format is that it felt groundbreaking at the time but in hindsight its hella too basic. A 'big bad' threatens the town. Buffy and co have repeated encounters with big bad, before defeating it. Mix and repeat. It worked for that show, but I think it'd absolutely come across as a bad way of doing business in today's TV.
I still maintain a viable answer is season long arcs = no, but episode to episode character continuity = big tick.
This is really the danger of arc stories in general. Some shows manage to pull them off, but consider the number of shows people became invested in (eg. X Files, Lost), only for the arcs to become tangled, confusing and covoluted, and the resolutions of them ultimately feeling unsatisfying. Even Buffy ended up falling hard into this problem eventually.
I agree that sci fi has far more potential for plot driven or character driven arcs. Farscape is a good example.