LOL... yeah, TelecomZombie is right!
Anyways, I think for most of us (at least for me) the idea was to test the SIP functionalit and see that it does work...
Whether we use it would greatly depend on the amount of coverage of wifi each one has, and whether the price of such calls is priced lower than the normal cell calls.
But no, generally, nothing useful is free in this realm...(and when its "free" you usually need to listen to a ******** of ads or crap, so in the end you waste your time, making the cost of time much greater than just paying for whatever service you wanted - at least in my case)