Did You Know Whatsapp Calls Are This Cheap?

I've had various reasons to make calls across various countries recently, I noticed that I had been recharging very large sums just to make calls.
I don't know what prompted me to try a WhatsApp call, but I did, and I cannot regret it.
I made a call to the UK for an important discussion and guess how much mb if took for a call of almost an hour? 13mb.
So, technically, it is much more beneficial to subscribe for data, than to make an international call directly. This is wonderful. Thank you WhatsApp!
See attached.