On both macOS (late 2014 Mac Mini / Big Sur) and Linux (Xubuntu 18.04 / i7 laptop) the results were the same.
After pairing the device, launching Audacity, and selecting the JBL as the playback device, playback through the JBL worked reliably. The sound quality is not as good as through my usual (wired) system, but not bad for a portable speaker (I'm quite impressed with this JBL speaker).
One thing that I noticed was that there is about half a second latency on playback. Press the Play button, and there's about half a second delay before any sound comes out. This delay is also noticeable with other software.
The "JBL Charge 4" claims 20 hours running time on a single charge. The speaker does not use a "sleep" mode, so it is always available. However, if for any reason the speaker does temporarily disconnect from the computer, then Audacity will show the error message:
After reconnecting the device it is necessary to "Transport menu > Rescan Audio Devices" before Audacity can use the speaker again.Error opening sound device.
Try changing the audio host, playback device and the project sample rate.
I was rather impressed by the robustness of the bluetooth connection - I took the speaker away from the computer to the other end of the house while Audacity was loop playing, and it didn't miss a beat.
This mini-review is by no means an endorsement for using bluetooth speakers / headphones. For sound quality I would choose wired speakers, and although I experienced no connectivity problems, I imagine that any speakers / headphones that go to sleep to save battery life would be very annoying.