Since Linkplay (parent of Wiim) has ex-Google staff and connections with Google/Alphabet - it's unlikely that Zidoo/Eversolo can have this kind of access to get "Chromcast Built-In" capability - in fact "Chromecast Built-In" seems to be pretty rare amongst audio-only products...
I compared the Chromecast to Wiim vs. Bluetooth to DMP-A6. I can't hear any advantage to one over the other so I guess it isn't really needed.
The DMP-A6 is a great product as well as the Wiim Pro Plus. I'm interested in seeing where the Wiim Ultra fits in. I don't see any point to the DMP-A8.