If what's needed is the ability to monitor them, then why are these things remote-controllable?!
Obviously read-only access to some sensor is not the same attack surface as having the ability to remotely shut-down the refrigeration.
That’s exactly right. There all all sorts of read-only architectures where the device can be monitored without every directly accessing it:
- The device’s control has a radio transmitter that emits its readings, but no receiver. Listen for those messages to monitor it but there’s not a physical path to reply to it.
- The device’s controller writes a database or message queue. Its code never reads from that source. Monitors listen to those messages.
And many, many similar methods with the same core concept: the item transmits its status but doesn’t have a method to receive replies. You just have to commit to using any one of those thousands of mechanisms.
The fridges are cheaper to make because they don't need a bunch of knobs and switches and temperature displays - just an app on employee phones.
Read-only access is mostly an illusion that itself can be hacked to gain control.
Same reason website's are remote controllable. There's someone who's job it is, is to make sure the fridge is up and running, 24/7 and for the same reason that website operators/SREs don't live at each POP/DC, that fridge operator wants to remotely be able to flip some relays off and on to fix the problem without having to drive onsite, if possible. Additional, a single person/fewer people can then also be responsible for multiple/more sites.