No it's not the only difference. How about:
1) You can't add an administrative user without using the metro user app to create the user and follow up by switching to the desktop app to promote the user to administrator. How stupid is that?
2) No more safe mode with F8. What happens when Microsoft Windows update installs a fscked up video driver (like it did to one of the machines I worked on) and it no longer boots with video? 8.x has to boot to working WINDOWS to force a reboot into safe mode. How stupid is that? I guess we'll never need to go to safe mode unless Windows is working properly. Sheesh
3) That God awful abortion of "fast shutdown and startup." Good luck getting rid of root kits and virii if you don't know the tricks to get Windows to actually reboot the system.
4) Windows 8.x shills and apologists always point out that installing "classic shell" or "start8" makes it usable. Why in God's name should an end user be forced to install third party software to repair the functionality intentionally gutted by Microsoft? The last Lenovo I worked on came with a replacement start menu app preinstalled. Of course, the Windows 8.1 update removed it. Which is 8.x? A half-ass desktop OS or a half-ass tablet OS?
I could go on, but you get the picture. Windows 8.x's user interface and user experience are a piece of shit. I don't care if it plays games or copies files faster. I wouldn't pay for it if it was $15. I wouldn't use it if it was free. Every time I am handed a 8.x machine, I think there is no way it could suck more than I have already seen. Every single time, it proves me wrong.