A linear regulator will throw the same heat.
6V bulb on 5V power will live about 7 times longer. This is a VERY common working condition. My ex school specified 130V lamps for 117V power to reduce re-lamping costs.
The flip side is that it is dim and inefficient. However that's moot for small meter lights.
If you have two lamps, put them in series. Same/less heat in the resistor. Drawback is that when one fails, both go out.