The thing why some players do play with T2 40 Stars is because if they are good, they can beat weaker low star players with a 2HKO provided they do not lose any round. This is because beating any 5 Star card can reward a lot of points. Usually 5 Points for a 2 star card that pulls it off.
The issue with 40 Star decks that use only 8 cards is that it can be difficult to pull this off.
If any T2 Deck pulls it off, they get 5 Points for winning + another 2 points average for winning the rounds while the opponent only gets 3 points for not winning any round. It can make matches pretty quick
-The 5 points comes from (25-Number of Stars at hand). Naturally, being a 40 star deck, it is 20.
-Then the points for winning the rounds
-Points for KO.
They can average 9 points for each match. Usually 12 for wins.
In the case of 2 lower star, just winning 1 or 2 against a full 40 Star deck despite losing, it is possible for the loser to get more points.
+3 Points for losing
+4-5 Points for winning with lower star cards on each round.
In this, they can get at least 10 points for losing as long as they win some rounds. In the event of a winning, they get even more points.