First of all welcome to the RX. As to your question, when a bookmaker posts an opening line it is, in theory, with the intent of getting equal action on both sides of the line, however, the line is moved by money wagered. Half points can and do make the difference between a winner and a loser many, many times.
In your examples, Stanford had to win by 5 for you to win. If the number was -5, Stanford would have had to win by 6 for you to win. If they only won by 5, you would have pushed and had no action. Arizona State had to win by 9, which is exactly what they did (66-57), so you won. Had they only won by 8, you would have pushed. In your hockey examples, the over 5.5 and 2.5 means the total must be 6 and 3 respectively for you to win. If they score 5 and 2, you would lose. Thus, you can see the half point or half goal is very important and can be the difference between and win and a loss. Bottom line: The half point or goal is not the same as the whole point or goal.