[Sylos]

In my personal opinion, the reasons for using it don't outweigh the reasons against it, but either way, the reasons for using it ( / an app store in general) are:

1) Convenience: You don't have to search all over the web for your software and don't have to click through an installer when installing (because everything is packaged in a standardized way and can therefore be installed in a standardized way, too). Also, there's a centralized way of distributing updates now, meaning that not anymore each and every piece of software has to come with an auto-updater.

2) Security: If you don't install your stuff from the internet, you're also much less likely to install from a wrong source and therefore less likely to catch viruses. If there is a virus-infected app on the Windows Store, it's also possible for Microsoft to remove it. The UWP-apps that Microsoft is pushing along with their store, are also sandboxed, so again, much less likely for software to be able to damage your system.