Ability to stop skin downloads could be useful.
When joining IGTC mid race to take over a car, you only have 1 lap to get connected and be ready to drive. If you have some of the normal connection issues and need to retry a few times, then download skins for cars and helmets, you could miss the opportunity to take over the car.
If you had your teammate shouting over VOIP to get your ass in ASAP, you could click the button to cancel remaining downloads.