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 It also helps with patching and auditing security so seems odd that these supermarket ones were out of date.