One shows only a few shops, often the ones that pay the most, the other shows the true number of different places in the area.
WHAT? HOW DARE YOU INSULT OPENSTREETMAP, THE MOST USED DIGITAL MAP!
(In all seriousness, I wouldn’t be surprised that OSM is actually used the most, especially because it creeps into many other maps. But of course, this usage is spread over many apps and not a single advertising map product, where GMaps is undoubtly the biggest one)