There exist plenty of tiny camera drones, except those aren't autonomous. An advantage is that crashes are less prone to damage (less mass => less momentum and kinetic energy), and if they do get damaged, repairs are [typically] far cheaper.
I don't know about battery life, though, and that might be a large disadvantage of those. Also, fitting a GPS unit into one might be tricky.
What happens when the battery is low or when I give it a tad too much spin?
"Whoops, did I just lob my $500 gadget into solid concrete?"
Well, I suppose it probably has safer take-off modes, too. Can't wait until they shrink it down to tennis ball size.