Take this UCO micro lantern for example. You will find below that it has other purpose aside from providing light.
Collapsing lantern is made of aluminum. Lantern holds two tealight candles
Glass chimney creates a windproof environment for the candle. Attached bail and chain allows lantern to be hung anywhere.
Burns all varieties of tealight candles.
So what's its other use? It can keep your coffee warm for 8 hours(that's how long a tea light candle lasts). I don't have my stainless cup when I took this picture so I just used a can to show you how.
That's all folks! Thanks for reading.