The echoed stars should disappear when you press enter, that way you are not revealing this information when you share a screen capture.

Surely looking at your screen seconds/minutes/hours later is the greater risk vector?

ATM keypads are very carefully designed so that all the buttons sound exactly the same, so you can't lift a PIN by recording the sound.

I've seen this demonstrated, using "Cherry" type keyswitches, with about a 75% success rate.

I also knew an old guy who could tell what an ASR33 or Creed teleprinter was printing just by the sound, with "good enough" accuracy, and copy RTTY by ear with "good enough" accuracy.

He didn't really talk about his time in the Royal Signals in the 50s and 60s very much.