Off topic but related, more and more I am seeing other bikers using lights both front and rear during daytime while riding.

For years I have used a flashing red taillight in daytime when bike touring or when road riding in overcast conditions. Sometimes two taillights.

But in the past few years I am frequently using a headlamp too. This is coupled with the purchase of dynohubs, if I was still using battery powered headlamps I doubt that I would be running lights up front. But with a dynohub, since I can't even feel the extra drag and with LED lights that don't burn out, there is no reason not to leave them turned on unless I am charging something with a USB charger.