Now, Canonical has proved what I have been saying for quite some time - the company is starting to look to its bottomline more and more. It's been seven years and a bit since the first version of Ubuntu was released and Mark Shuttleworth does not have bottomless pockets.
Hence Ubuntu for Android, one more way to make a bit of money. The music store, the cloud, are also efforts in that direction.
The idea, if examined dispassionately, is plain silly. Why would one have, on one's mobile, a system that can be used only when one is docked into a bigger device? Wouldn't it make better sense to have that system on the bigger device itself?
There are bits and pieces of Ubuntu that one can use on one's mobile - but the existing system already has all those bits, a good example being a way to handle one's music. And there are bits which do not come along with this beast - LibreOffice, for example, isn't there, one has to use GoogleDocs.
The only word for it is that ubiquitous one which describes everything and nothing - cool. FOSS people are also big on another meaningless word - awesome. The latter covers everything from well-designed software to the underwear that someone bought on eBay.
The public information about Ubuntu for Android make it plain that this is a binary - there is no mention of source, though I presume that source for components which are under the GPL category of licences will be available - which offers some of the functionality of a full Ubuntu system.