Perfect for when you connect to a WiFi router which forwards the data through a mobile 4G Broadband connection (common in cabins and other remote locations). It provides a simple overview over the total you have used for each wifi network. (Should have had a sum total of all wifis too). It sadly lacks an individial tracking of how much wifi each app uses (similar to the mobile data usage in iPhone settings), which would have been very handy. Some apps are very greedy in the background when on WiFi. (I would have paid more for this feature. If it wouldn’t kill the battery on my iPhone.)