I definitely perceive it as a flash, and that the light is constant on. It's no different to two lights mounted very close together, one on and one flashing, IMO.
Attention grabbing FTW. The flash is so powerful that it often causes drivers in a queue to move out of my way, either mostly because they're being kind, or because they think I'm an emergency vehicle (had a couple mention that to me).
btw., that video I posted, needs to be seen on a separate window as I noticed the resize for embedding has dropped enough frames that the flash is no longer regular as it is in real life.