Why Not to Use Desktop Linux

Because it can do even better as a server, leaving the desktop stuff to a real desktop system.

Gentoo GNU/Linux in a Hyper-V, with a Gnome Terminal (Sakura) on the Windows Desktop via X Windows* forwarding over SSH. Along side Samba to use Windows File Shares (or putting a Unix network file system on Windows) it is like having two operating systems on the some machine.

Much better than duel booting as you can remove the Linux system without running into Grub issues and you can use both at the same time.

P.S.:
X Windows allows OpenGL rendering to be done on the machine the window is on, thus using the Graphics Driver installed for Windows. Video Drivers for Linux can be a pain, so this is very nice.

* I use VcXsrv for the X Server, and PuTTY for SSH.