The reason why I dropped it to Rank 15, to put it simply, it's related to the clan. For the clan reward, you can get "Tokens" for free, "10 tokens" for 200 wins, "50 tokens" for 1000 wins, "100 tokens" for 5000 wins, and "160 tokens" for a total.
If you win once in the arena, you will get a box (you will get it if you win 5 times). This is because it can be difficult to get a box easily, so some people think that it can be easily obtained with 1VS1 and dropped the rank.
I've seen several troll mechas, and the troll mecha is trying to kill you instantly using MAX things such as weapons, drones and feet. I can't win with a low mecha. In that case, please run away from the match immediately.