My random guess: freezer need temperature audits and franchise supermarkets have to prove they're properly managing the food. If the central monitoring service can also alert/dispatch staff within minutes to deal with issues, it becomes a pretty attractive proposition.

Something that might not be obvious, but temporary dips in temperatures also need to be monitored as it's enough to spoil the food. Worse case scenario isn't to have to throw 50~100 kilos of food, it's to have spoiled food still looking fine and consumers ending at the ER, with the whole franchise name on the news.

> My freezer at home

That can't be your frame of reference for a business entity part of a franchise.