Where did I assume that? I use battery lights on my less-used bikes (the Cateye GVolt - not Volt - and Axa Greenline look the closest to my now-obsolete ones), but I really hate those nasty wide-beam torches from
ebay which have now become bright enough to be dazzling. Dynamo lights tend to be aimed once and then left on the bike, whereas most battery lights are reattached every trip, but the nasty torches have to be aimed so close to the front wheel that they are almost never set like that and are an anti-social nuisance.