In my experience, [delay: msecs] is far, far more reliable than other types of scheduling. I don’t know if delays are scheduled differently than runIn() on the backend, but I do know that I’ve had a smartapp using delay (to trigger my hot water recirculating pump to pump for 27 seconds) running for 18 months, and it’s never once failed.
“never once failed” is not a phrase I can apply to any other part of my ST setup.