Why is champion mastery actually terrible

levels 1-5 is just playing and only actually gaining points from winning, not playing. you could feed and win the game and still get a huge chunk of points towards levels 1-5. then 5-7 is totally reliant on getting an S, which you dont have to win the game for, you could lose but have a good kda and cs. why is it not like this for all levels? it shows you are good with your champ. seems off