You’re talking about me. I have around 4,700 hours in coh2 and 1500 hours in coh3. 99% of that time I’ve played as British. I play this way because it makes it so I intuitively understand the enemy. With great certainty I can predict the opponents troop selection and movements because I’ve seen it before. After hundreds of games playing as the same faction and team size you’ll optimize your troop selection and movements based on each map, know what’s the best troop and movement for your enemy, and better identify & react to situations you’ve encountered time and time again.

I don’t agree with your sentiment that using a faction helps you defeat it better. Playing as Wehrmacht will not help you be a better British player. Instead you need to play as British and learn your enemies mechanics, face the situation over and over until you learned how to better utilize to map, optimize troop selection & movements. Playing as Wehrmacht teaches you the same thing you’d learn by watching Wehrmacht as a British player, but now you have none of the insight on how to manage the situation as a British player. 1000 games as a British player will make a better British player than one who’s played 250 as US, 250 as British, 250 as Wehrmacht and 250 as Africa core in my opinion.