See John 12:6
Well done!
But Jesus said, "Leave her alone! Let her keep what she has for the day of my burial. (8) You will always have poor people with you, but you will not always have me."
So, aside from the obvious point that Jesus appreciated a bit of bling - bling (cool), we learn from this incident that Jesus knew what was going on, and spoke plainly to Judas. He did not call him a thief before the others, but he knew.
Judas did not learn. That, I think, is the point of his life. Parrot the teachings all you want, if you don't accept the Christ, your words and your acts won't help you.