Of course, getting seen - but also to see yourself! In cities, it is no problem with all the ambient light, but doing night rides myself outside the city, with zero ambient light I
depend on having a good frontal spotlight as well - else I would damage the wheel quite easily when hitting a hole or a peak stone. When driving fast in darkness, on small paths between meadows and not on the streets, you need light, and over a sufficient distance so that you can react to holes, stone, etc.
I therefore use these, which I would always recommend again, they are a very solid allround-solution. The backlight is no tiny but bright dot but a 12 cm-wide bright bar with 2 LEDs and a prism, the front light is a 60 lux spotlight combined with an ambient light-sensor and a 4 LED position-daylight that also serves as a stoplight when sitting still. Sometimes it gives the impression of a flying lightcloud approaching you, that bright the daylight can be.
When pulling an trailer, I additionally use this very bright eye-killer for it:
That thing is bright, really. Too bright in fact, it is a good idea to mount it such that the beam is directed to the ground, slightly. In Germany, I do not dare to run it in flash mode, it got me once into a longer conversation with a cop.