NymphCast has been around for years but it's still basically unheard of. This has more polished marketing (and a less weird name) but other than that I don't see what makes it any more likely to succeed.
There also isn't a good open source DLNA server (presumably because of the above issues).
Presumably you still need some kind of media server for the fcast receiver to stream from when playing local media, I assumed that would be dlna based but what is the actual idea here?
Edit: And then there's stuff like Plex and Kodi too with existing servers and clients for numerous platforms. I'm fairly sure I can "share" a URI to the Kodi app on my phone and the Kodi server will stream it. I remember that working well but it's been a while.
I prefer having an app that can save progress and remember what I've already watched. (As a younger person I could recognize a show or movie from a glimpse while surfing. Nowadays I find myself rewatching for several minutes before recognizing the program.)
Instead, I hope to have receivers that the user can install if they wish.