Ubisoft's The Division is trying a few interesting ideas — one of those being a companion app designed for mobile phones. Except that's not happening any more, with the concept nixed by developer Massive Entertainment.
Speaking with IGN's Evan Campbell, a "representative" for the studio confirmed that the app will no longer go ahead. The IGN story mentions that app "'created an imbalance' that compromised gameplay".
This statement isn't expanded on, but given the app gave users the ability to buff other players, it doesn't seem like there would be a sure-fire way to stop someone from using it to give themselves an unfair advantage.
It's definitely a neat idea and one that seems awesome on paper, but comes undone when executed. We're likely to see more cooperation between mobile and console / PC as time goes on, but we first have to solve these sorts of problems for it to be viable... and fair.