I totally agree that this painting for $50 million is a total waste. It would have been so much better if the buyer had given some of the money to a good charity; or if they have a business; give some bonuses or a raise to the people working very hard for you to have an extra $50 million to waste. There is no real spiritual or mystic message that the artist put into it.
Christian mysticism and symbolism can be very profound. IMO, the real purpose of that is for people to be guided so they begin practices to realize God within themselves and the outer world.