1. Wifi calling directly uses your home's wifi to place the call while the Pebble uses your internet connection to broadcast an LTE signal which your phone uses to place the call (once VoLTE is enabled). Before VoLTE is enabled, you don't place calls through the Pebble, it only boosts data. After 2-3 weeks, VoLTE should be enabled on the Pebble allowing simultaneous voice and MMS which wifi calling doesn't allow mms (but if you have a decent signal you can receive MMS without issue while on a wifi call).
2. Yes, any user can piggyback off the signal but I noticed the footprint isn't that large and didn't extend outside my home. I wouldn't be too concerned with that.
3. If you disconnect the device they will send you warnings that they will charge you if you don't reconnect it or send it back.
I recently got one of those Sprint pebbles that was sent even though i did not request. i finally set it up after nearly 1 hr of fighting with it. I was wondering:
1. How is this different that Sprint wifi calling ?
2. Can other sprint users outside of my house piggyback off this pebble ?
3. If I stop using the pebble after a few months, do I need to pay the $70 or is the $70 only apply if you never initially set it up ?