Everybody should have a shutter over the camera, just to protect from blunders and misclicks.
No matter how you trust your software, some malware may want to activate it, especially at a high-value target like Zuckerberg (or Bezos, or Nadella, etc).
Why not cover your camera? Some MacBooks are so delicate that Apple itself warns stickers can break them IIRC¹, but to me that’s just one more great reason never to buy a MacBook. For other cameras, if someone can look into my windows, they can also watch a lock-picking video on YouTube and IIRC learn that something like ≥70% of American homes have locks from the same 1–2 brands, and break in easily, but I still close curtains, because why not?
Don't know about laptops but on recent desktop motherboards the jack detection and output/input switching is done in software. Probably the case on many laptops too. So this approach shouldn't be considered a "hardware switch" as it's still possible to capture audio from another mic even when a headset is plugged in.
On both of my XPSs I can switch to internal or external mic regardless of a headset behind plugged in, so the snarky suggestion to use a cut-off headphone jack is misguided and won't work on many modern laptops.
No matter how you trust your software, some malware may want to activate it, especially at a high-value target like Zuckerberg (or Bezos, or Nadella, etc).
Alas, microphones are not as easy to deactivate.