Contrary opinion, or at least Some food for thought. I have and use a mini-USB rechargeable headlight., Actually, I have two, I ride one while the other is charging. I still have an old battery-powered blinkey taillight. I'll probably replace it soon.
But, were I to do another self-supported tour, I almost certainly would go with battery powered lights all around. Yes, there are work-arounds for portable charging of USB devices, and I probably would carry one for my smartphone (mainly so people have a shot of tracking me if I go missing) but having to to recharge the lights is an additional layer of complexity I would prefer not to have on a fully loaded, self-supported camping tour. For a "credit-card camping" tour, yeah, rechargeable is good.
Them's my thoughts, and they are worth exactly what you are paying for them.
__________________
"I'm in shape -- round is a shape." Andy Rooney