LibreELEC itself does not run under Windows. It has its own small Linux operating system, so it's not a simple application that you can run under Windows. You will need to install Kodi itself in Windows if you want to use it that way.
Kodi vs LibreELEC... Windows is a bulky full-blown OS that requires at least 20-30 GB these days, LibreELEC only has the bare necessities to run Kodi and runs off a 512MB partition + storage of 4GB (basically a USB stick). Windows has an internet browser, LE does not (really) IMO. Apart from, you yourself will know what you use Windows for.