There is nothing particularly new about face recognition software. You can even download your own version for your photo collection (just Google "Picasa 3").
The only thing to remember that it is only face recognition - there are no additional biometrics in there. In which case it is not doing more than the human on the immigration desk and is arguably doing a lesser job because it cannot recognise signs such as nervousness or agitation. Neither can it become concerned that a child travelling with a single adult looks afraid or unhappy.
It is simply another way of cutting the labour force - not a way of doing the job better or faster.
As a matter of interest - came through Edinburgh on Friday. Six of these booths. None were operating. Same story last two times through Birmingham UK. So what is the story?