I am surprised that this feature took so long even though the tournaments were there in front of the tower.
Currently, you cannot show anyone that you are in a 10 box community. You have to go to Elvenstats to check it out or read what's in the guild description.
I can hardly imagine that this feature goes beyond that and offers top tournament players individual rewards, because INNO would exclude 90% of all others from winning these rewards ... or do you know, for example, a Chapter 6 city that can currently win a tournament or a trading town in any chapter?
No.
There may be an additional guild reward possible, but I wouldn't bet on it.
From my point of view, the trophy will be the reward and nothing more.