If you have Chromecast-enabled playback software, then yes. Windows Media Player can't do it, as far as I know, but Google Chrome, for example, already allows you to stream stuff. Other software certainly exists as well. I have my music on a NAS (Synology) and control the playback via a Chromecast-capable Android app (BuhbleUPnP, AllConnect, DS Audio, ...) from my mobile phone. This works flawlessly. The mobile phone only plays the remote control. This also works if the music is on your PC instead of a NAS.

For me, this device was necessary to make MultiroomAudio thanks to the integrated chromecast. At this level, the JBL Playlist was obsolete 3 months after its release, no update planned for the device, it took several minutes/hours to reconnect to the speaker group, resets often necessary to get something some time. Now, with the huge delay in updating the JBL Playlist's built-in chromecast, it's not even worth trying. I had bought two, one blue one white, same problem, programmed obsolescence/incompetence at work? In bluetooth, everything works. For the rest I don't know. I'm not sure about the rest of it, but it's a good idea to avoid it at all costs, unless you're only using it for bluetooth!

This product is not recommended for the intended use. Possible moisture damage may result in loss of warranty.

No, the unit must be plugged into a wall socket. It is designed to be carried around the home and plugged in wherever you want to listen to music. If you want a "really portable" speaker, I recommend this one: JBL Charge 3 (Stereo, Black)