Yeah it's just based on his profile as a player across his career rather than judging him on his first game. We know what kind of player he is.
It's not so much that I don't think he can be one of the best around in that role - there I agree we need to give him a lot of time to see how he gels with this team, and develops after this step in his career - but rather that I just don't really agree with bringing someone in that fits that profile. I wouldn't have wanted us to get Digne either, for example, even though he's clearly a very potent threat in this Everton team built around firing balls into Calvert-Lewin.
We haven't got the players to play that way and I would rather we build around the likes of Rashford and Greenwood as our attacking style than someone like Calvert-Lewin. If we do that, I don't see how we'll ever provide the platform for Telles to flourish. He might well be good value overall but we have a tendency to buy players that aren't very well suited to the roles we ask them to play, which mostly negates any value savings we've made.