To say "the recording continues" is not true, as the sound is not been recorded (it never is) nor is it being processed. Yes sound waves are entering the microphone, yes those sound waves are compressing/bending something and yes there's a change in resistance in the mic. But is the computer 'listening'?
The author takes care to point out that it's up for debate if keeping the mic online is a bad thing, but from my perspective I don't want an application grabbing data it has no business accessing until explicitly permitted, I don't like those "foot in the door" strategies.
What worries me more is that the macOS and iOS versions share the same SDK, so presumably the same "convenient" behaviour. I think I'll uninstall Shazam from my phone - just to be sure. I use it at best once every month so it won't be missed much (never installed the desktop version - one copy
is was enough).