The thing is a close kissing cousin to a "Betty Lamp" from an earlier branch of the family. Google has some great pictures of Betty Lamps.
Both use something to wick up the melted fat to where the burning takes place. The thing is, when you understand how a "fat/wick/lamp" works and then if you compare that with a hand full of candle stubs, to my mind there ain't no contest.
The ladies from the alter guild save me all the candle stubs from church. In my mind they are superior to just regular candles; much less wasted wax running all over the place. It seems they burn cleaner and of course as the wax is burned, they last longer.
Best Wishes, Rob