Re: it's irrelevant
I "grasped it" fine - it's just shit. It's an absolutely pointless and pathetic thing to put on a desktop PC.
As a simple example of its pathetic nature they've taken off the start menu button to replace it with a blank space. So they've saved zero space and now you have piss around hovering over the corner (very annoying in VMs and RDP) instead for _no reason_. Similar goes for the stupid fills-the-screen start menu -- you gain absolutely nothing at the expense of covering your entire desktop when you want to look for an application.
There are absolutely no gains in usability on the desktop and there is no need for metro to be on the desktop apart from MS's mistaken belief that doing so will help sell their tablets.