Why not create a battery that is composed of lots of these tiny batteries that could make a smartphone run for weeks???

But that really depends on which type of device we are talking about. Some devices (like cellphones), will let you send files over bluetooth and usually have a search function, making them easier to use for this purpose.

Yes, for you this may be the case. I also prefer data integrity in most of the cases, but sometimes you need the faster filesystem, because the data is not that important (temporary files), like cache and other data that will quickly be erased. So, like always, it depends on the needs of each environment.

VirtualBox is one of the best free (and open-source) virtualization app, but they already have Oracle VM that is based on Xen. That turns VirtualBox in another product wich fate we don't know...