Thats interesting I did not know this. Whats happened is it's measured the speed of boot drive (SSD), and decided there is no benefit. It's wrong because it would have helped the HDD. Sorry I took you down this path, it explains now why people don't use this approach with SSD as boot.
My drives are different, as I boot from a HDD, then use SSD for index's, page file, and readyboost. I'm slower to boot than if SSD was boot drive, but once windows and apps are established computer is very responsive. I take the view how your PC performs during the working day is more important (i'm a software developer) than how long it takes to boot. So like a duracell battery, when most PC's are paging to HDD drive, or repeat loading of data from HDD, my machine avoids most of this and it stays responsive even with many applications and data loaded. Even down to development code, and SQL Server Databases cached into the readyboost, these things actually speed up after a short while.