Excavators with tires instead of tracks tend to be chosen for the fact that they are very versatile. The fact that you can change tires on them, means that you can work even if you are facing harsh winter conditions. For an excavator, traction is very important. If the ground is covered with snow, you need to have tires that can handle those conditions and can offer you good traction.
Excavator tires can be chosen from the technical manual, which can guide you to the best choice depending on the tasks at hand.