I have found that my Google Cardboard has become a "show off" device as opposed to something I use.
When I first got it I remember being amazed by it for about two hours, including watching Adventure Time through it. The problem is though, is how used I am to multitasking. And I think this is the bigger problem with VR. When I'm watching a TV show, playing a video game, or whatever, I also want to be aware of the world around me incase an important email, text message, or call comes in. I think many people think the same way as well. And this is what I think could hold back Google Cardboard, and any other VR headset.
On the other hand, one thing that must be done with a Google Cardboard set is playing Vanguard (which you can find in the play store)