system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] Why did the Alliance use snowspeeders at the Battle of Hoth and not use X-wings?

Watching Rogue One, the X-wings seem to take down AT-ATs relatively easily and are able to fight in atmosphere. So why did the Alliance use snowspeeders at Hoth given that snowspeeders don't have heavy weapons like the X-wings?

I understand using the snowspeeders as scouts earlier in the film as they may perform better in icy conditions but when it comes to battle, surely the X-wings are a no-brainer.
gpt
Despite the fact space is very cold, it's actually very hard to get rid of heat - you have to radiate it all. It's why the ISS has *tons* of radiators.

X-Wings, designed for space flight, radiate heat *very* well. Considering the environment of Hoth, they'd simply exhaust too much heat. Machines need at least some heat in order to work (think how hard it is to get a car engine to crank over in cold weather). 

It's why they said they were having problems adapting them to the cold. During a prolonged combat, they might ice up and stop functioning.

Edit: Also note that the AT-ACTs are very lightly armored, so the X-Wing's results against them might not be typical.