WiFi makes it easy[ish] for consumers to firewall their IoT bullshit to inhibit spying. IoT devices with cellular radios promises to remove even this small level of control from consumers.

You can already buy a nanocell/femtocell. Probably with 5G and "LTE-WLAN aggregation" it'll eventually be easy to secure your network.

At least if enough people are willing to care about, advocate and pay for this feature.

That's the point. We don't know all of the future applications. But it's very unlikely to be nothing interesting. Do you think everyday appliances in the 50 years will function essentially the same as today? It's a very general enhancement in capability with lots of potential but currently unknown use cases.

I say this while also recognizing that most IoT stuff today is overhyped BS.

Yes?

A refrigerator will still keep things cold. A stove will still heat things up. An AC will still AC. Other than home automation systems that go belly up when their servers go offline, most things do the same thing they did 50 years ago.

5g isn't revolutionary.

Doing something substantially faster almost always leads to a revolution in it: internet, manufacturing, cars, planes, computers.

At every step, you could always say "it is just faster". Only in retrospect can you ever see how world changing "faster" was.

Manufacturer can bypass any user firewall.