The reasons it's a big deal is because the man is supposed to cherish his wife to be and honor her. So when he asks for her hand in marriage, he gets on his knee and asks. This is a very romantic moment that she will "cherish" the rest of her life. So by you proposing to her in this fashion, you are giving her a gift.
HonestSincereLoyalMan 26-30, M 2 Answers 1 Feb 14, 2012