I don't mind stuff that can also be controlled by my iPhone, but I abhor stuff that can be controlled only by my iPhone. What if I change phones? What if I decide not to carry a phone -- there was a time I deliberately didn't carry a phone because my technical attorney in NY was a phone freak who'd call me while I was having some quiet time out riding to tell me... that he was running in Central Park.
There's another consideration with stuff controlled by your phone: sensible people, at least where I live, carry their phone on the handlebars in a baggie of some kind, perhaps even a hardshell. That makes controlling the phone through its touchscreen something you need to pay attention to that is better reserved for keeping you safe from the maniac motorists. In my case, too, the phone is already dedicated to my heart rate monitor, and I don't want to be continually taking off my (dress leather, full finger) cycling gloves to swipe between apps.
PS Yesterday I saw a schoolboy on one of those gyrowheelies you stand up on. I want one of those!
So I dismiss anything that is primarily app-based as mindlessly unergonomic trendiness, and give it a miss. As for stuff that can be controlled only by a phone, tell me another one, see if I laugh.