> A typical IOT client sends a few bytes every few minutes or hours

That's the SigFox definition of IOT but not necessarily typical for all cases. There are several usecases out there which require slightly higher bandwidth and data rate, but not quite broadband.

One quick example is over the air firmware updates. Take MSP430. If we were to build a smart meter using a MSP430, our firmware probably be couple of kilobytes.

Likewise, the size of the data can vary upstream as well.