Docker is a system of virtual machines of sorts. Except each image is normally a single application. This is beneficial because if something goes wrong with an application it won't crash the whole computer. You can then delete the image and install it again without ever having to reboot your computer. There's also the cross platform advantage. Home Assistant and Node Red, for example, work on a Linux operating system. If you are using Windows, Docker would allow you to install the applications on your computer even though you aren't running Linux.