They are surely required when you can't hit the hot spot corners with your mouse; especially true on multi-monitor setups. The point you seems to be missing is that Microsoft seems to be intentionally making the mouse + keyboard experience dreadful in order to push their metro/touch agenda. Ignore those small truths if you want but like many have already echoed here Microsoft is yet again blowing another opportunity by making the desktop difficult under W8. Zune, Kin, WP, and now W8... No Compromises...Only Fail.
+1 Stupid, stupid, stupid design, but I guess I'm in the statistical minority and therefore it's irrelevant if it's made harder for me to use :-/