internal flash isn't a bad thing for a video editor - you wouldn't want to have your footage on your system drive anyway.
I can't see any relevant pluses (besides silent operation) too - size doesn't matter that much - pros would rather not spend a lot of money for new enclosures or replacements for their now homeless red rocket cards, video I/O Cards, LTO controllers, internal hdds, ...
also, a lot of people use adobe software (after effects, premiere,...) which gets a huge performance boost from nvidia CUDA cards (think times 30-100 for some rendering-jobs) .
the small form factor would make sense if it was rack-mountable - otherwise not so much. also there's no connectivity on the front - you have to turn around the whole thing every time you want to plug in an external harddrive - good luck with tons of cables already sticking out of it.
i could see myself buying one if i'd also had the money for an external thunderbolt raid and if adobe would port their mercury-engine to openCL (or if apple offered a BTO Mac-Pro with Nvidia Cards)