Smartthings Internect Connectivity

Is connecting a router via the network cable the only way the Smartthings hub gains internet connectivity?

I am wondering if there are other ways the hub can be connected to the web. My worry if if the router disconnects for some reason.

If there was a way to be connected via 3G or something then it is less vulnerable I guess?

There were plans for a cellular option on the Hub, but I believe that these plans have been cancelled, at least for the initial round.  I suspect a later cellular version will be made.