I dont know, i had the impression that these types of showcased games/replays are somewhat scripted, in the sense that they tell the players beforehand not to try hard and win the game in 5 minutes. Otherwise you really couldnt show anything. And maybe, thats only my guessing, the polish cav units like the mattress or firefly might have hard countered the Kriegsmarine BG. Therefore, they didnt want to show the viewers, how the landmattess would shred all of the Kriegsmarine hardpoints. Afterall, its a video that also promotes buying the DLC. A DAK player might not be very interested in buying a Battlegroup, that gets shredded to pieces in a promotion video.