Completely speculating as I don't know the situation in Europe, but some possible reasons are:

- Remote alerting for the store manager/head office to quickly respond to a refrigerator failure after hours, providing options for saving valuable stock (e.g. move stock to another refrigerator).

- Maintaining an audit trail for cold chain management (e.g. regulator says you must keep an audit trail proving that a frozen fish has been kept below -30oC since it was processed on a ship all the way up to point of sale in a supermarket).

- Refrigerator manufacturer says a condition of warranty is that the refrigerator must provide remote telemetry proving some warranty condition has been met (e.g. regular cleaning cycle operated).

Note: all these speculated reasons are unidirectional data flows. So even if a valid reason exists for Internet connectivity, why can't it be limited to unidirectional data flows?

Some large supermarkets (in the UK at least) sell their capacity to the National Grid so it can be balanced in times of demand. They agree to turn off their freezers for a set amount of time to create a "virtual battery".

Not just that. But why the fuck is the control software so weak? Why does it allow remotely bumping temperatures to near boiling without any checks? Which idiot designed this system? Why aren't they out of business? Same with the people who installed these systems. Why on earth didn't they think to secure it?

Supermarket freezers are a bit more complicated than that. They can run at different temperatures and can consume a lot of power, so are part of a bigger store HVAC and electrical system as they may load-balance. Stores do not have qualified engineers on site to do anything with refrigeration equipment and it is better to have minimum wage offsite monitoring than expect a minimum wage shelf packer who only gets one toilet break a day to care about the fridges.

I don’t know about supermarkets but for medical freezers it’s useful to be online for monitoring and calibration.

My org has lots of freezers that need to be at precise temperatures. Sometimes they drift so you have to check them a few times per day, log the check, and adjust as necessary. Doing this for a thousand freezers is tedious and error prone. Networking helps. “Cloud” lets it all be done remotely without getting IT very involved for vpns to be set up with specific vendors. It also helps with patching and auditing security so seems odd that these supermarket ones were out of date.

On top of the monitoring mentioned by others, it's also to create a centralized log of actual temperatures. This then lets you show inspectors that you are keeping up with refrigeration requirements.

What I read from the last wave is that supermarket changes how cold freezers will run depending on how much customers they expect that will open and close the doors. Just having the freezers adapt based on the temperature of every single moment cost too much electricity or can result in unsafe temperatures.

For commercial uses some kind of global monitoring is not super crazy. Regular retail freezers being on the internet, that's the crazy talk.

Likely so that stores can be monitored remotely. A lot of supermarkets have a centralized orchestration somewhere, especially big chains.