More drain on the world's supply of both balonium and unobtainium.

You can't store enough compressed air to make it practical -- perhaps
they use a very long air hose?

The claimed range was (IIRC) something on the order of 40 miles - and
they said it would do 70 Mph. To me that makes for a practical urban
vehicle, whereas most of the electrics are not.
As others have said, what is needed is a thorough test by the
automotive Press. We'll see.

David Johnson