You get more rewards as a friendly antag, not to mention you get your affinity as well. I've been in random queues at 40%-50% MMR, you "win" at a 5.5 to 6.5 rating and get "rewarded" for "winning" and get 1,500 gold, feels like losing anyways. I get 2,200 gold losing as an Antagonists, LOL. Not to mention it's just a horrible experience when you go through the high solo queue MMR. I suggest playing as friendly antag for anyone wanting to lower MMR, it's more lucrative for both you and the raiders.