I suppose this might be useful in the context of shoots where there are 'clients from hell' who could otherwise be crowding the studio or getting underfoot on location. I nevertheless pity the poor DOP who will be bombarded with the opinions of all those who insist that it is part of their job descriptions to have and to express opinions.
The 'video assist' technology is said by some to go back as far as 1956, with the comedian Jerry Lewis claiming to have patented a system. My first experience with it was in the early eighties at the Bavaria Studios here in Munich. It may have been a help for Wolfgang Petersen, director of The Never Ending Story., although my recollection is that there needed to be two or three large gentlemen ensuring that only a privileged few could see the display on the video monitor. That I fully understood... the last thing I would want as director is well-meaning inputs from multiple sources... good cinema is not created by committee!
The idea of the camera output going directly in real-time to iPads and smartphones... well, I guess I am getting really old.