This formation blocks attacks both from the wings and from the middle.
Suppose one of your players sends a long pass to your right winger, he will be marked by 2 players, the DMC and the DL. Two interceptions can be made, one in front of your player and one behind your player. So, even a through ball won't work, because the player from behind will get it. Even if your winger manages to get the ball, he still has at least one player to beat.

So, focus only on flanks and using long passing may not work. It is better to use mixed passing and mixed focus.