In what way will Pope Leo and King Charles praying together today be significant for the Catholic Church and the Church of England?

Both men prayed together (not separately) in a public service of worship in the Sistine Chapel. Buckingham Palace said this is "a significant moment" in relations between the Catholic Church and the Church of England, of which Charles is Supreme Governor. My question is, **“In what way(s) will this event be significant for both religious groups?”** This question is about how this one-off event, where two world leaders of two religious groups pray together in a public service of worship might mark something “significant”, either with respect to the past, or looking to the future.