Agreed it could be useful, but counterpoint, I used to work in a local only grocery store back in the 90s. We had temp gauges hanging from the evaporator units blowing in the cooler, and temp gauges in the customer facing side as well. We'd look at them, and if they're out of range, we'd call the maintenance company. I mean, stores are staffed by people, even downsizing, someone has to go into the walk in fridges and freezers to put stock away from shipments and restock customer facing areas. I dunno, seems like a solution that doesn't have a problem.