It most probably isn't that simple, because... Well, let's not forget what IoT devices are. Devices who use a processing unit to compute certain functions. That, by definition, is called a 'Cpu'
IoT devices mostly try to use some energy efficient cpus, because their whole added value doesn't stand in the processing power, but it's still cpu. And as computers Aldo tend to become more energy efficient, the 'gap' between those so called 'IoT devices' and what we call 'computers' (especially laptops) is getting thinner every day.

So to make a difference between the most energy efficient computer (cpu) and the most... Powerful IoT device (I'm thinking of autonomous car for instance, this kind of thing will definitely require some calculating horsepower), looks like a brain killer to me.

So I guess it's more a matter of getting the largest possible adoption, ti spread the hashrate as much as possible.

And mot to forget that the initial promise of uplexa is not to name someone rich by mining, but to cover at least a part of the energy expenses used to to make those device's work.

Which is, whether gpu and powerful cpu are allowed, absolutely possible already...