Re: What's the need they're trying to fill?
Blackberry's niche was hardcore government and big business security. BB products had (have?) security baked in from the hardware up and they were receptive to the suggestions of Government agencies such as GCHQ and NIST.
For that reason for a long time Blackberry products were the only ones signed off for use within high assurance organisations.
But BB sat on it's hands for so long that Government users began to hate their BB and crave the fondling delights of iOS. BB then decided to make a jump for the wider public and try to sell to the yoof market that worked for while until they got bored of the BB offerings too. So they ended up pissing off their old market and losing their grasp on the new.
Meanwhile other companies started to sniff the pork from Government and began to make their products more enterprise orientated except Apple who allegedly told the security services to take a hike 'coz we're Apple'.
It seems now that BB has realised that they've made an arse of their dalliance into the feral over supplied public mobile market and they're starting to court their old customers again.
I suspect if they can get it right then they may pick up some of their old customers that still like physical keyboards and proper security. However new boys like Samsung are getting signed off for high assurance work as well so the future is less than certain. Plus executives are as prone to the whims of fashion as anyone else, BB ain't fashionable so the Passport better be a phenomenally useful tool or it'll just get ignored.
Myself a few years ago I'd have bet a small amount on MS buying up BB's security patents when they went bust. I still think that might happen yet. If the Chinese buy BB expect the Government accreditation to be dropped like a red hot turd.