If you think that is only 10% of what they do, what we see CSGO coaches doing is what? 0,1%? Hahaha
"actual experts" have the same information we have, to judge coaches, they are not magical beings that can hear what the coach is saying for the players when they ask for a timeout.
Don't fool yourself like that. They can in fact judge TEAMS and PLAYERS way better than us, because they have advanced knowledge for it. The only way to judge a coach is by the way they talk with the team, for example, zews LOOK very active, he seems to take the team lead when they are in a bad situation, he talks a lot and is incisive, while other coaches LOOK like they are dead during a whole match, barely saying anything. Again, it is whats it LOOKS like, we can't know exactly.