I’m assuming he attacked me with something WAYY closer to my own power level, but why would he hit me and then revert his team to something so low? is there some sort of tactic or advantage you get by doing this?
With a weak defense, he will lose a lot and his cups will drop low.
And then he can fight weak enemies.
This way, he can fill the raid chest faster, by claiming 5 easily dead enemies each match.
And if you fill after raiding back up. It will have better value.
This is a practice commonly known as “cup dropping”. Some players do this to intentionally decrease their trophies so when they look for an opponent, they would be matched with a very weak team and they can crush it with a much more powerful one. It helps fill your raid chest faster since you are pretty much guaranteed victories because you are fighting much weaker opponents.
On a side note, I engaged in cup-dropping myself a long time ago