Why it works
Retros die when they depend on people remembering a week's worth of friction on the spot. A standing prompt collects the raw material while it's fresh, so the actual retro is spent deciding what to change — not staring at a blank whiteboard. The three questions never change, so one scheduled email runs your retro for the life of the team.
Make it yours
Send it a few hours before the retro so replies are fresh. If you've dropped the live meeting entirely, add a fourth line — "one action we'll commit to" — and you have an async retro end to end.