Not all the things we cherish are bad. If I cherish my child, that is a good thing.
Children deserve to be treasured.
If I treasure money, that is not necessarily a good thing unless, I'm giving it away. The text doesn't give us specifics. What it does say is that while the shepherds were running through Bethlehem, proclaiming her son as the promised Messiah, she kept the matter to herself. There are several reasons. The angels had already made a spectacular announcement.