LEDs look great at night and they can be useful to help with orientation even in the day. Maybe more useful still, you can use programmable LEDs like this RGB WS2812B light board to indicate flight data. By using different colours, you can program the Naze32 and CC3D flight controllers running Cleanflight to indicate battery warnings, flight mode, thrust levels and even RSSI strength. For example, you could program a fading pattern from white to red as you throttle up. If you want to keep it simple, you can set the LEDs to just sit at a solid colour.