Head- and tail lights definitely help make bicycles visible from the front and back, but what about from the sides? The handlebar-plug-replacing SideLights are designed to address that shortcoming, plus they serve as headlights, tail lights and turn indicators.
I like the idea of bicycle turn indicators because I often can’t safely take my hands off my handlebars to do hand signals, but 300lm isn’t bright enough. That’s $9.99 Home Depot flashlight levels of brightness.