These seem to be the actual brightness numbers from Magnic. If I understand this correctly, to comply with StVZO, your SON+Cyo puts out its 60 lux at all speeds above 15kph (about 9 mph). As you can see, the Magnic ramps up in brightness as speed increases - like the generator sets of yore - and doesn't output 30+ lux until the cyclist is pedaling at a speed of over 37 mph.
Thanks for finding that. I really wish he had whitepapers available on these subjects.
Yes, it's very clear when using them that the amount of light output is highly dependent on how fast one is going. Slower riders probably would be better served by something more consistent. As I understand it the next version (iC) should work more akin to a traditional dynohub setup.
I find them more than bright enough for my needs, but their output definitely doesn't set the world on fire.