When you kill boss you can invest more money into farms again so instead of keeping farms you must kill the boss asap so you can turn the defense gold into farms. If you kill the boss in 1 round you lose only 1 round of income.
Congrats on the run! Looks awesome, 2 unfortunate moments I saw on t4 ace hit boss on magic and not support, idk if it's intended. On t5 ace went full dum dum mode at the start flying away from the boss for like 20s.
Got my first top 3 medal this week. 2nd place in 3 player with a time of 55:56. Luckily the 2 people i queued up with left so i could do it solo very easily :P
He probably has, he most likely just finds the dreadbloon the easiest, or the easiest to get a record in, or maybe he just really likes the dreadbloon.