My belief is that is more about convenience than anything else.

It is also worth looking at why this is so, which most likely stems from the lack of technically inclined staff in every location and the cost of having a tech going from store to store everyday to deal with POS, back office computers, amd any other kind of device.

Now, can you secure all this? For the most part yes, but it is quite expensive to do it. Maybe they will do it now or they will go with “it cannot happen to us twice” thinking and not do anything substantial about it.

It's not just about having tech inclined staff, but just the whole staffing strategy in general. Most grocery stores et. al. try to staff as cheaply as possible and try to have their workers do as much as possible during their shift. This means that there's no extra time available that they're not shelving products, or sitting at the register.

Rather than have extra staff at the store to do stuff like monitor fridge performance, it's better to have them report stuff centrally and have someone or some tool monitoring thousands of fridges across the entire chain. This way you can send out repair teams and plan maintenance more efficiently.