The disruptive WiFi-first models of SIM-only MVNOs come with some major benefits for both consumers and network operators, but these services have struggled to turn popularity into profitable businesses. That was until FreedomPop, which claims it is set to record its first ever net profit by the end of this year. That will represent four years of effort, as one of a group of US pioneers of the WiFi-first model. But FreedomPop now claims it is converting nearly half of its users in the UK to paying subscribers, a strong sign for a freemium model whose profit potential has sometimes been questioned. FreedomPop’s service launched in the US in 2012 and then expanded to the UK last year, operating as…