Not convinced really. Don't think there is a substitute for a life-saver, making eye contact with drivers and a big arm signal.
Them being close together may not help with the differentiation of which way you are turning, but motorcycles seem to manage.
You would presumably want to use them all the time which would mean taking them off the bike everytime you leave it, not just in darkness as with regular lights.
However, I can see there could be circumstances when they would be useful, when both hands are really needed on the barsfor stability/setting off but signaling is also needed (I'm thinking of a local double-mini roundabout here)