I think this was tongue-in-cheek. Nobody would actually want to take a native C/C++ Audacity, port it to WASM, and then wrap it in Electron to make it a "desktop app" again.
On the M1 Mac I actually measured lower CPU usage during audio playback on WASM compared to the native desktop version which uses Rosetta. I'm not sure if the slowness is due to Rosetta or a performance bug on the Mac port.
Not the sort of safety issues I think you mean, but there have been some rather questionable behaviours from the current owners in the last year or so. A quick search for Audacity here or elsewhere will find the details.
especially if it's opt-in (which is provable since the project is entirely open-source) -- can people simply _not_ opt-in if they disagree with telemetry?
Audacity segfaults all the time when I use it. Don’t make it sound like it is more stable than it really is. Security bugs are a subset of bugs, of which Audacity has many.