Sweden has Swish with over 4 million users.
Norway also has a hugely popular p2p payment app called Vipps with 2.7 million users.
Disclaimer: I work for Vipps AS
Ah, sorry, Swipp was the Danish MobilePay competitor that died due to Danske Bank's disgustingly unfair play (they were part of the Swipp group, but started MobilePay development in the background and launched before Swipp did). I was of course referring to Swish.
MobilePay passed 3 million users in 2016 (out of ~7 million people). I don't have any updated statistics.
Anyway, with your added numbers, it is quite clear that at least in Scandinavia, person to person transfers are very common.
In Denmark, the MobilePay system is massive, and challenging credit card payments.
It is designed entirely for person-to-person payments, and only later added support for shop purchases as a lower-priority feature. It is used for all sorts of things, including splitting bills and selling used goods, all legal.
Sweden has Swish, but I never figured out if it was popular. MobilePay, on the other hand, is huge.
Edit: "Swipp" -> "Swish". Swipp is dead.