I'm guessing this may be related to use of iOS? I'm running Android - and can operate (i.e. play/pause forward/backward) all streaming software via the lock-screen - without having to unlock the phone.
I've tried this on: Plex, Netflix, Spotify, Google Play Music, Youtube, assorted local tv broadcasters, etc. Still have not found a single chromecast enaled app which does not let me operate it via the lockscreen.
Personally - I found my ideal device in Chromecast. It is very easy to set up and use (heck, even my girls (7, 10, 12) and my wife finds it easy to use). And the experience in using it is un-surpassed. I much prefer locating my content on my phone than on the TV via a clumsy remote and interface. It is also extremely easy to switch from, lets say, a Youtube video, to showing a Netflix movie. While the youtube movie is still playing I will be lining up the next item to play. And when friends are over we can all contribute music videos to the playlist, etc.
I'm guessing I am biased the other way around - being a linux and android user primarily - but I still can not see how anything can surpass the Chromecast experience. Nothing is even close - and I have tried them all.