@CrazyWizard It may be you are correct in regards to the Vonex...

@CrazyWizard
It may be you are correct in regards to the Vonex domestic offerings (mobile or landline) in truth I have not checked their landline charges - because Vonex is primarily a business orientated phone company. And their product is scalable PBX business phones for $39.95 a month per handset - including handset and unlimited calls. It behoves one to start up a little online biz.

With regards to the App - it will work on any digital device - irregardless of the carrier - it is most definitely not tied to Vonex. Calls using the App made to PCs laptops or net connected phones/tablets/phablets or whatever you want to call them are completely free of charge. It is only when you go ofnet to a landline or mobile that a cost would be incurred - for that you would have to have Vonex call credits.

So then, why would say, a Telstra mobile user choose to call another person with Oper8tor?
Because there are more chances to get through. The App does not have to call a persons mobile if it detects they have skype or various other applications currently running. And Oper8tor will call via the least-cost-path. If, for instance, our Telstra user was actually calling another mobile or landline using Oper8tor, the calls would be charged at VOIP rates - so cheap - especially for international.

So anything with a net connection (that could even include a digital reader - if you had a dongle) could be used as a defacto mobile phone. If you have no Vonex call credits it will not be able to call out to mobiles or landlines and it will be entirely restricted to net calls - but the App itself is agnostic - it'll work on Apple or Android devices and ANY carrier you happen to be using.

Not dealing in fake hope. Thems the facts.