Not using advanced stats for your own players makes sense. You see them every day. You know exactly what there is to know about them and how they are and how good they are.
But advanced stats give you insights in players you haven't watched in every moments of their career. Even if they are flawed in some way, they will still give you more information than no information.
I'll add a bonus. It also helps avoid players just shooting for no reason and doing actions to better their advanced stats at the detriment of helping the team win.
But they are probably using numbers to evaluate their team, I mean, you kinda need to at some point :p