Libraries allow easier jumping off points for different types of file storage. The standard documents, music and pictures can be on different drives if you want them that way. You can add a new library that points to something else. Let's say your precision program creates its own set of folders, you could have a library go directly there. The cloud is also easier to incorporate this way.

However, I don't use that too much. For most of my common stuff, I use the Pinned files and folders feature that comes with Windows 7 through 10. It took a bit to transition from XP, but I like that much better than the shortcuts that XP had.

Oh, I like some of the wifi stuff much better on the newer versions.

For your usb to serial issue, a couple troubleshooting steps I'd take is to make sure that any power saving settings are turned off for the ports. Don't plug in the serial adapter until after the computer is fully running. Windows might see it as a mouse if it's there on bootup.