Because with the data plan, your maps get loaded without having to connect to someone else's hot spot or wifi where you are flying. Pretty hard to sync with no map... It's just best to have the plan so that if you get a chance to fly while traveling, like I do all of the time, the maps are already loaded and ready. Having the Shield on wifi and the Ellipsis with Data, I'm always having to turn on the hot spot on the Ellipsis so the Shield can get the maps. The Ellipsis is always ready and has a great signal coming in compared to my Samsung S7 Edge. I can have no signal with the S7 and usually 2 bars and 4G with the Ellipsis when there is a signal, so it has become the main hot spot for traveling unboosted. When I bought the Shield I thought that it could be connected to Data but with lollipop it couldn't. It cost us $10.00 a month for the Ellipsis to have data and living in the sticks, we can use it as a hot spot at home also when the DSL goes down.