They basic idea is to be noticed/recognized from as far away as possible.

Bicycle lights are small and not very bright. Small solid lights tend to be lost in the background.

Lights that flash are noticed farther away than lights that are the same but solid. That's why lights on airplanes, buoys, and antennas flash. An irregular-like pattern might be more noticeable still and might counteract any possible "mesmerizing" effect. Rapid flashing seems overly irritating.

Nothing is perfect.

I'd use a flashing mode (that isn't high frequency).