I think the "soundproof" is the selling point, so really it's a matter of how sound-proof it is.
No one would want it for an office...but if it's truly sound-proof, I can see it being used as:
a recording studio
study nook for students as mentioned
video conferencing
call centers maaaaybe
gaming pod
meditation pod
but I'm guessing it's more of "sound dampener" so useless for everything I just mentioned.