The trade-off
A high line squeezes the space the opponent has to play in, keeps your team compact, and lets you win the ball closer to their goal. The cost is the grass in behind your defenders, which is why the high line lives or dies on the press in front of it and the keeper's willingness to play as a sweeper. Push up without pressure on the ball and you're just inviting balls over the top. The Athletic's piece gets into the coordination it takes; go read it.
Why it's really a trust exercise
Here's what I'd tell a young team: a high line is something you commit to together or not at all. If one centre-back doesn't trust it and drops off, the whole thing has a hole. If the forwards don't press, the line is exposed. So this is as much a culture topic as a tactical one — it requires everyone doing their job on the same bet, and it requires players brave enough to hold a high line knowing they'll occasionally get caught. I'd rather build that collective trust than have a team that defends deep because they're afraid. Defend high because you believe in each other, not because I demanded it.
