This low power argument makes far more sense than the high-bandwidth cases normally thrown around, especially because a lot of iOT can be outside where the signals aren't blocked by walls or near a for purpose commercial antena. I can imagine some server based interactive gaming/UIs only if the rest of the backend also improves. Fast refresh VR could be another use-case, if they didn't get so heavy and hot for other (non data) reasons.
Just getting more spectral efficiency when signal strengths are high benefits all users. Lots of towers are at saturation over the air now, so if we can squeeze more bandwidth out of them, traffic that is presently being delayed will do better... even before we account for growth.
That is, 5G isn't just mmwave; it's also getting more out of existing low and mid band spectrum. (And mmwave, of course, will unload the other spectrum too somewhat in the densest areas).
The more interesting feature in 5G is the signalling for IoT devices, those that wake up infrequently. Metering devices, handheld payment devices, patient home monitors, security systems, Airton, etc.
5G isn't really about more bandwidth but always on and more efficient use. This will enable more than just phones and a few tablets.