The three windows computers on wifi have limited purposes with no need to be automatically or continually be connected to the internet. I do connect them by wifi for various tasks including security and windows updates. I always do this early in the morning when on Bonus Zone time.
Unintended consequences of allowing an automatically connected computer would include forgetting the date I allow the computers to run windows update. If this happened at the wrong time I could spend a few GB of the limited service plan data.