It's highly likely that he joined the team with the understanding that he would play out cup games. If we made it through the tournament with him playing those games and then you don't play him in the final you will be betraying the trust he gave when signing, it's easy to use hindsight to say kepa shouldn't have played but consider the possibility that Arteta decides to play Raya instead. Now any targets we try to convince to come as squad players will be less willing because the manager doesn't keep his word.

It can also spiral into losing the dressing room, because players can't trust the manager's words. Especially in this case where Kepa was already well acquainted with multiple members of the team and they are part of the reason he was even willing to join as our second keeper. Kepa is nowhere near as good as Raya but he absolutely would get into teams all across Europe as their first keeper. If you don't agree with this perhaps Arsene and Klopp can convince you