Blinking lights allow higher maximum instantaneous illumination at a lower average power expenditure compared to steady illumination. For battery powered blinkies, this means the light can be bright enough to get noticed over background lighting clutter or at longer range without draining the batteries too fast.

That said, I am also a firm believer in continuous visibility for improved tracking when at relatively close ranges, when motorists' accuracy at estimating closing speeds is most important.

Therefore, I always use bright rear reflectors in addition to a rear blinking lamp. At closer ranges, the reflectors provide good continuous visibility while the blinky provides good long range conspicuity.

For the front, however, I am less interested in very long range conspicuity than I am the accuracy of motorists' estimation of my closing speed. In my experience, under conditions with little or no overhead street lights, drivers who are preparing to cross my path on the roadway are reliably conservative about not pulling out in front of me when I use a bright, steady white 250 lumen headlamp mounted on my handlebars. I cannot think of any situations where I felt that I wasn't visible enough to drivers in front of me or that drivers ahead of me underestimated my speed.

I think it's possible that under urban condititions with lots of overhead lights to provide some tracking visibility of cyclists wearing bright clothing, an energy-challenged headlight might be more attention-getting in flash mode while ensuring adequate range, therefore being a benefit. However, my own commutes take me through enough dark areas that I need a bright enough headlamp to see the roadway, and my Cygolite Expilion's lithium ion battery capacity is adequate to cover my entire commute a few times over, so I prefer to run mine steady whenever visibility is an issue.

Some pedestrians have remarked that my 250 lumen headlamp, while being aimed at a reasonable down angle, was painfully bright. However, I think the main reason for this is that some people tend to stare at bike headlamps out of curiosity, while they know better than to do that for much brighter automobile headlamps.