If they can be used like that, why couldn't they be used... as phones?
Changing phone every two years is not sustainable, even if the old phone is used as an IoT wall terminal: it's still "consuming" one phone every two years. In a sense, an old phone in a drawer uses less energy than an old phone staying powered to control a lightbulb.
> planned obsolescence
Nitpick: I like to call it "premature obsolescence". Planned obsolescence is the idea of engineering the product to not last more than some time. I think nowadays it's often not the case; rather we engineer the product to last for the time of the warranty (1-2 years) and not more. And a product dying after 1 year is "premature", even though it was not actively engineered for that.
If you upgrade a phone to get a new one with a better camera, well, the processor on the old one is probably decent still, it could be a mini PC where the camera quality doesn't matter.
Also, it's a status symbol, you can't just _not_ upgrade.
My feeling is that phones are not evolving that quickly anymore, though.
> If you upgrade a phone to get a new one with a better camera, well, the processor on the old one is probably decent still, it could be a mini PC where the camera quality doesn't matter.
Sure, but if you didn't need the mini PC in the first place, then it's not more sustainable than throwing it away. It's actually less sustainable, because now you consume energy for a mini PC you didn't need.
Not saying people should not get their new toy. Just that they should not pretend it's sustainable :-).
> Also, it's a status symbol, you can't just _not_ upgrade.
Around me it's become more and more of a status symbol to not upgrade. It's sometimes almost a competition of "who has the oldest phone", and nobody is impressed by someone buying the latest iPhone. So... it's not the same everywhere :-).