>>7633507a snowspeeder having a tow cable makes sense, considering how important towing capabilities are are in ice and snow areas.
You have to remember that air speeders are basically just cars and such in the Star Wars universe, but objects are still placed on the ground and will need to be moved around by the ground as well.
Anyway, snowspeeders existing just makes Star Wars a little more believable. it's like how the army doesn't have just one armored vehicle or one jet. There's a multitude of military equipment that exists to fill various roles and niches.
This is why there's such a fight against multi-role jets/vehicles/boats, because they dont get the job done properly and seen as inferior to specifically made equipment.