... ask anyone with serious motorcycle miles and they'll tell you about the same thing.
When I was riding motorcycles as a daily driver, I modified my headlights to keep the low beams on when the high beams were on, simply for visibility - it gave me a "wide, multi-color front bar" (low beams were HID, high beams were upgraded incandescent, outer markers were yet different colored) that improved people seeing me. Another bike I did the same thing to, so both headlights were on normally to improve visibility.
I ride sidecar rigs now, which have a "wide, weird lighting" layout (central headlight on the bike, but a sidecar light too), and I'll ride those at night. But the one remaining two wheeler is just a single central headlight, and I won't ride it at night for exactly the reasons this study found - you can't tell distance/speed/etc from a single headlight without any other context.
Serious rider here. Riding is my primary transportation.
I used to ride at night much more often years ago, but I've basically modified my lifestyle to the point of just avoiding riding at night at all regardless of lighting situation. After enough close calls with drivers who just don't pay attention, not to mention in the city I live in drunk driving as well as aggressive driving is sadly very common.
To be honest I even feel less comfortable driving at night even in a car, for the rare time I drive my girlfriends car after enough years of just avoiding night driving.
When I took the MSF (Motorcycle Safety Foundation) basic rider course, they had everyone turn on the extra headlight by default, with that exact explanation.
When I was riding motorcycles as a daily driver, I modified my headlights to keep the low beams on when the high beams were on, simply for visibility - it gave me a "wide, multi-color front bar" (low beams were HID, high beams were upgraded incandescent, outer markers were yet different colored) that improved people seeing me. Another bike I did the same thing to, so both headlights were on normally to improve visibility.
I ride sidecar rigs now, which have a "wide, weird lighting" layout (central headlight on the bike, but a sidecar light too), and I'll ride those at night. But the one remaining two wheeler is just a single central headlight, and I won't ride it at night for exactly the reasons this study found - you can't tell distance/speed/etc from a single headlight without any other context.