The Snowspeeder was always a weird one to me. Why not just use the attack space craft?
However, X-wings work in the frigid -450f of outer space?
In the original canon, there was a separation between spacecraft and “repulsorlift” craft which operated close to planet surface. So, X-wing and TIE “starfighters” wouldn’t be able to maneuver and fight in lower atmosphere.
Over time, they relaxed this in games and comics, I think because TIE fighters are iconic, and they never had the Empire use something like the airspeeder in the movies.