Did anyone take a screenshot of the Mic Drop button before it was removed? There are GIFs showing the sent email with the minion, but could find any showing the /button/ in action.
Seems obvious this was a bad idea.
Edit: Google's animated gif showing the whole UI: https://1.bp.blogspot.com/-GYnAKaZY9v4/Vv2RkU5hIcI/AAAAAAAAB...
I would guess they missed the idea that people use muscle memory to close irritating pop-ups without trying to figure out why it's there, or what it relates to. They are then left with 2 send buttons, one with a now ambiguous microphone icon.
That's, of course, not what's going to happen.
They might have reacted differently to an actual dialog at first click that says "This will inject an image into your outbound email, and mute the conversation. Continue?" (with the default choice set to "NO".