I prefer to stop/slow down, than rely on the horn to make me safe - both on a bicycle, car, or motorcycle.

This Sunday, on a motorcycle with 2 lights up front, I was still invisible to drivers from side streets, because the sun was low behind me. In a distance of about 10 km ride, 2 drivers had pulled, then raised a hand to apologize for not having seen me. Slowed down before the intersections, ready to stop/swerve.