I have never heard of it, I guess that is a good reason to kill it.
Yes, Microsoft had a Maps app. And, of course, it was excellent until market winds shifted.
See kids, the ancient sages used a compass and a Hagstrom map they could never fold twice, regular-old folks printed directions off Mapquest, and the young kids just assume Google Maps has always existed and has trouble understanding how Moses got lost in the desert.
But, for a brief window of time, there were PC-based mapping tools. I was a huge fan of Delorme Street Atlas (arguably the pioneer in the space, with CD-ROM releases going back to 1991), and Microsoft was a direct competitor with their admittedly-prettier Streets and Trips alternative. In addition, there was Microsoft MapPoint, an onramp into the GIS market - I once used it to make a map of all of my contacts in Microsoft Outlook...but, I digress.
For that window between about 2004 and 2010ish, it was possible to use one's laptop and a USB GPS receiver to navigate to a destination.
Then, of course, the idea of having a laptop-sized screen in a car went out of vogue, and it was tough to sell map data on CD-ROM anymore, so the data was basically used to feed Bing Maps, which was part of the Windows Phone 7/8/10 releases...and, I'm pretty sure you know the rest.
Now, the app being killed here, specifically, was the one that first shipped with Windows 8 and was the default "map app" in Windows 10's early releases, but to your point, exceedingly few people used the app, because they were much more likely to go to Google Maps or Bing Maps in a browser, and the desktop app was little more than a wrapper around the website data anyway. I tried it once, just for kicks, to see if I could get the app to work with the Streets and Trips GPS. It took a bit to find a compatible driver, but I did, and while my old copy of Streets and Trips picked it up just fine, and while Windows itself liked having another source of location data, the Maps app wouldn't perform the same task as Streets and Trips, even with a first party GPS. Apparently the use case wasn't meaningfully considered, so there was literally no advantage to using the app over web-based solutions.