From the FAQ
"Subscription editions are similar to regular Creative Suite products in that they are installed locally on your
computer. The functionality of a subscription edition is no different from that of the regular product. You do not need to be online constantly to use your Creative Suite subscription; however, you will need to be online when you install and license your software, and at least once every 30 days thereafter. The software will alert you if you need to make an Internet connection for a license status check."
So in the off chance you lose your internet connection on the day your subscription needs renewed, that would be your only concern