Samsung's suite of apps, including the likes of Notes, Gallery, and Cloud are now available to non-Galaxy Windows machines. This wasn't the case until now - only Samsung's own laptops could use these proprietary apps.
But users are reporting that they are now able to download the apps to non-Samsung Windows devices. You can find Galaxy Notes on the Microsoft Store on your Windows device and download it, no Galaxy Book needed.
Some apps require you to sign in to your Samsung Account in order to work. Galaxy Notes gives a disclaimer upon launch that it has been optimized to run on Galaxy Books and that other machines could have some issues.
You'll find a surprising number of apps in the Microsoft Store when you go into Samsung's dev account - Notes, Cloud, Gallery, Screen Recorder, Galaxy Buds, Bixby, Samsung Studio, and Phone to name a few.