I did something similar
I pinned not only my desktop but the "legacy" apps I use most frequently to the Start screen. A single click on any of them opens them immediately with the legacy desktop as backdrop. The legacy desktop remains even after the application is closed. The Start screen is accessible the same way it is from everywhere else, should I ever want to return to it (which sometimes I do, although not often).
Now when I first boot up in the morning (which is MUCH quicker), instead of having to double-click on an app to open it as I did under Win 7 and before, I just single-click on the tile. That right there is an improvement to efficiency, albeit minor, that is unarguable by any objective observer.