There's absolutely no reason for a flashing light above 200 lumens (peak lumens). You blind the drivers who are closest to you. Flashes are very good at getting noticed but they make judging distance challenging. This is especially true for lights with a narrow beam pattern that have an insane hot-spot.
The reason flashers more noticable is that your peripheral vision is designed to detect motion, so the flash shows up as motion.
Light and Motion has a mode that's closer to a sine wave output. So rather that a sharp flash, you get a smoother variation. It helps reduce blinding while providing some modulation to help your eyes notice it.
As for the brighter is better, once you get beyond a certain brightness its not making you safer. It makes little difference if you can be seen from 2 mi away vs 1/4 mi, you're just generating road rage. You want to be visible enough that drivers have plenty of reaction time. At 60 mph, a 1/4 mi visibility is 15 sec, that's plenty. In most circumstances, sight lines will be significantly less than 1/4 mi.
Not long ago, it was simply impossible to have a bike light that would be remotely comparable to car headlight. Modern LED lights will have hotspots that can significantly exceed car lights (due to shaped beams). Cars have headlights and it doesn't stop them from colliding. You don't see the safety people advocating that cars should always drive around with their high beams on. A super bright light in blink mode is no different than driving around flashing your brights at everyone. Sure, you're more visible, but you're also an anti-social <insert censored word>.