I think staring at a portable device looking for traffic that may be present is in itself a safety hazard. If indeed this sort of stuff makes us "safer" I am asking safer from what?
Safer from bird strike perhaps? Safer from Aussie Bob who never uses such gadgets? Safer at the scene of the last mid air? (VFR approach point at YSBK if I recall correctly)
I don't care if the data is shared or not. It will not show me. But I do have a window which I use regularly.
Now don't get me wrong, I am not saying this sort of thing is useless, but to harp on that lack of data sharing is a safety issue is drawing a pretty long bow. In any event, I hardly know anyone other than the odd private pilot and his mates that are using it anyway.