Many times these stores have floor cleaning machines - either robotic or driven by a human. An employee could zip-tie their sensor to it, let it do its cleaning trip around the store, and return to collect the data later.

This would allow an employee to do several stores in a town in a single day. And potentially less chance of a workers-compensation claim being filed if they fall down while walking around looking at their device.

It's been said in one of the comments that the initial mapping by a human takes like 2-3 hours. Knowing the speed of a Roomba, I guess that it would take much more time to do it. And 'humans' are COTS devices available on any department store (sorry ;P).

IIUC, the black dots have to be mapped by hand. I.e. the human has to drop pins on the map. A Roomba doesn't know where it is a-priori