No they are not and explicitly banned in some country. The strobing light is way more blinding for any other user of the road. It also makes it hard for you eyes to adjust. This means that you struggle to understand how fast the bicycle is moving, and exactly how its moving (and therefor anticipate their movement correctly), but you also get blinded which might prevent you from seeing other user of the road (especially pedestrian and other bicycle). With strobing light, you not only putting yourself at risk, but every other user of the road.

And flashing lights are not filtered out? How can traffic even exist during Christmas season?

A continuous light at least gets perceived as a path through image space. Strobes on the other hand can easily fail at getting perceived as belonging to the same unit of light source when there are many other illuminated dots (xmas crap! rain droplets!)

I’ve read the strobes are bad because it makes it hard to see how close or far you are. Maybe the best thing is to just wrap yourself with some battery powered Christmas lights…

Strobes are much harder if not impossible to effectively gauge the distance, bearing, and speed of. They are insufficient.

Both a bright solid light and a much dimmer strobe provide all of the benefits with none of the down sides.