I have seen this video, but I have never tried it myself. There are two reasons. First, it is not safe to keep warm with an open flame. I choose the latter between cold and warm and safety. Secondly, it is not unreasonable to do only one experiment in this way, and it has no practical value. The reason is that the heat generated by candle burning is very limited, and the baking hand is ok. It is too high to say "heating".