Have a friend shine a 100+ lumen strobe weapon light at you at night and try to aim at you friend (with your finger NOT an actual weapon). Then tell me it doesn't give the person with the light a blinding advantage.

Never use a weapon light in the on setting or you will be a target. Either strobe it or just pop it on and off quickly as you scan the room lighting up corners or places too dark to see even with adjusted eyes (natural night vision).

Another technique for weapons lights is to hold the hand gun out to your side. You can a laser with this technique or just learn where the shot strikes within the light's pattern. Practice low light engagements and give this a try. Your assailant will only be able to see the light and fire in that direction which is a few feet to your side.

I have used both techniques with SIM rounds and they work even against people who know the techniques too.