My understanding is that if you surrender a game, it doesn't count for weekly/season game completion.
I also think that in arena, you lose all your rewards for playing the game too (coffee, tears, etc...).
Based on this, I find that it disincentivises surrendering, even when I have obviously lost and neither player is having much fun any more. Sometimes it can even feel disrespectful not to surrender, when the opponent does a great play and destroys me.
It also means nobody wants to surrender a stalled out game.
Overall, my experience of the game is worse that it could be because of this.