I think it's not a real "serious" product; more of a "gag", if anything.
I think it was Google's way at having fun with all the VR hype around last year's I/O conference (and to show it's not anything really groundbreaking).
A bunch of Chinese companies started pumping out Cardboard clones pretty much as soon as it was announced and at least one commercial VR porn company is using them.
I think it was Google's way at having fun with all the VR hype around last year's I/O conference (and to show it's not anything really groundbreaking).