Yes I use these, when I can't get clipped in fast I can still pedal reasonably elegantly!Only time it's happened to me was a loose cleat on new shoes, couldn't get my foot out
Ref difficulty clipping in, double sided SPD pedals help a lot
My bad habit is waiting at lights and leaning beyond my centre of gravity on my clipped in foot side and then panicking and overcompensating back to my unclipped side.
I forgot to dry my wet cycle shoes after a ride a couple of weeks back and had to cycle on the flat sides with my trainers the next morning, felt really unsafe now I'm used to clips.