Thank you all for all the additional info.
I have tried the app quickly, not exploring much, it's a definitely a good option, still limited in a way, right ? In my personal situation, If I work on my laptop it's more convenient to control the music from the player on the same machine, especially with Gigs of music stored on hard drive (no streaming for me, I torrent music and save over the years).
I found the sound output option (HDMI), and even the media sharing option (screen captures) if this may convince users to give a try to Linux (Ubuntu or other distro). Very easy to setup.
I still didn't read enough the documentation yet to understand how to send music signal over wifi (instead of bluetooth) to play music from other room. I will keep looking.
Thanks again for great help.
Definitely the Yamaha setup is fantastic.