Obviously a desktop linux ("lightweight" or otherwise) makes more sense on a desktop than a retrofitted android, since android will always be, first and foremost, a mobile OS.
That said, android's app stores have produced, in a fairly short timespan, an entire ecosystem of polished, useful apps that users love. Without android, many of these applications wouldn't exist at all.
As a developer, a regular old linux distribution on my desktop makes more sense[1]. As a normal everyday user who just wants the additional amenities offered by a big monitor and a real keyboard, "android on the desktop" makes more sense.
[1] - I'm actually partial to FreeBSD.
Also, while ChromeOS may make sense for schools and businesses that have adopted the cloud fully, I'm not sure ChromeOS is that good of a option for regular consumers, other than having a more optimized interface for the desktop (a lot more than even Windows 8).
But for a consumer, does ChromeOS offer that much more than Chrome for Android?
Retro-fitting Android onto desktop devices isn't the solution, there are many lightweight linux distributions if you want an actual desktop OS.
Animated desktops atleast to me are a gimmick, and the reason other linux distros haven't been able to optimize their graphics is because of the desktop parts and unreliable drivers (Nvidia & AMD), now most of these micro-PCs use mobile parts (ARM Cortex processors, PowerVR graphics cores.) which have readily available open-source drivers or OS-optimized proprietary blobs.