Originally Posted by
noglider
... I also find that I am not annoyed by people wearing helmet lights, and I haven't had those shine painfully in my eyes. The painful lights tend to be on handlebars, but the problem is the light and the usage, not the placement.
I suspect most people with lights on their helmets are using headlamps designed to go on their head for camping. And those usually have a pretty wide beam so that you can see a large area close up. Some of those headlamps are quite bright for runners that run at night, such as ultra marathoners and need the brightness for jogging or running speeds, but they still would be using a wider beam than a typical bike light.
And the most common headlamps are very light weight, lighter than even light weight bike lights, thus not a lot of battery capacity.