For those of you with an Apple Watch. The watch itself has a pretty impressive microphone and the built-in "Voice Memo" app is incredibly good at recording for long periods. After starting a recording, if you return to the watch screen there's no big "give away" that recording is happening.
I've started doing something similar to the Author of the article. Whenever I feel I'm entering a conversation I'll need later I start recording.
Recordings autosync back to the phone, the "Voice Memo" phone app can skip periods of silence, AND best of all the recordings can be easily exported to other things.