Assuming you'll never run both at once (e.g., one as a VM guest in the other), the only difference will be how it is seen on your network. If you think of the machine as the same host, just running different OSes, then one name suffices. If you think of each OS as a different host, then having separate names maintains that distinction on your network.
Your router, f/ex, may log internet accesses by host. Do you want that logging to be kept separate for each OS or for that physical device as a whole? Do you want to address that device from another one (e.g. for resource-sharing) with a different name when it's a linux box than when it's a Windows box? Or is it just 'the node that shares its printer', regardless of what OS is running?
I think of a hunk of hardware as almost bland until it has a configured OS running on it -- the OS and its configuration are what give its a personality -- so I give each OS-configuration running on a specific piece of hardware a unique name, including my guest-OSes. Actually, that's not quite true - I have a guest OS that I move back and forth between a desktop and a laptop. To me, that is one system with one ID. YMMV.