As long as you don't have to wait too long for games to pop it's always worth it. Even after you get 5/5 hateful you can still turn in 100 arena points for 2k honor... if you get fast queues that's like 7k honor for 30-45 minutes of losing in 5s (also helps to not get 2k teams that try to pillar hump your 15k hp shamans all day). Probably a better return on time than a lot of bgs.