I love that the Ian know exists. But after I learned it I tried it for a while and it didn't stick, I went back to the classic knot I learned as a kid after a week or so.
IIRC the reason was "yield" - I found my Ian knots were often wonky. So you save 2-3 seconds but the tradeoff is mental energy for doing "QA" on your shoelace knot!
But that was many years ago, I should try again. Maybe you just need more practice.