why was so important for the king of france to be crowned, re joan of arc?

It was the belief at the time that Joan of Arc was blessed oleh God and visited oleh angels, and religion was extremely important back then, especially to Royals, as they believed it was their God diberikan right to rule. So, to be crowed oleh a girl who was blessed oleh God and had the support of most of France would have boosted the King's authority.