Annoying... can you see the blinky while it is flashing? Is it annoying you? If it is (possibly) saving your life(!) is that not (possibly) a trade-off worth making? Delibarately shining your helmet mounted 800 lumen MagicShine in a drivers eyes is annoying, no one considers that stupid behavior, using a flashing taillight is not considered annoying by drivers. I have never heard even the most rabid bike hater really get excited about blinkies. They have simply become accepted as an is.

I was getting a ride in a car the other night, and in the sea of taillights up ahead I could see a blinky flashing. I couldn't see the cyclist, but I could see their blinky. It said to any car behind them, for at least a quarter mile: "up ahead there be a cyclist, make of that what you will". The majority of drivers will be grateful for the heads up. A solid taillight simply would not have stood out in that sea of redness. What I know from actually using my own eyes and experience vs parroting tired (and wrong) myths and anecdotes is that a steady light is just as unlikely to provide any meaningful extrapolation of a cyclists speed as a flashing one. Moreover, it simply does not matter!

Relative to the speed potential of the humblest economobile, a bicycle is a stationary object. Most motorists make that assumption automatically upon seeing the blinky flashing. When they get close enough to actually overtake the bike, their headlights are providing all the information they need about the speed (or lack of it) of the bicycle they are overtaking. It works. It works so well that by subverting what has become a convention of nighttime bicycle equipment, the contrarian cyclist hurts, rather than helps their overall safety. FWIW.