That's basically because of my Side Decking habits. I side at least five cards against any given match-up because I actually want to draw those cards. To accomplish this, I have to put very generic cards in my Side Deck, like Smashing Ground.
That means that I'm not siding cards that are auto-wins against certain decks. An example of that would be Light-Imprisoning Mirror in the Lightsworn/Zombie format. You draw Light-Imprisoning, and you win against Lightsworn. Instead, I'm using cards like Banisher of the Radiance, which don't win duels on their own, but help significantly against a lot of different decks, like X-Sabers, Gravekeeper's, Frog Monarchs, Fish OTK, and Lightsworn.
However, because the Gravekeeper's match is so bad, I may have to break this habit. Closed Forest is basically a free win against Gravekeeper's, so siding three might be justified. Along the same lines, Ally Salvo is also very one-dimensional, but it kills Skill Drain in Hero Beat, which can cause me trouble.
Fortunately, the format has slowed down to the point where I can afford to wait to draw these cards. I would wait for them in the same way that I wait for Scrap Chimera: if I open with them, I can start aggressively, but if not, then I merely stall the game out until I can draw into them.
Unfortunately, besides simply not drawing the cards, there's a huge downside to Side Decking like this. If I were to go up against a rogue deck like Gladiator Beasts, I wouldn't be as prepared, since I would be dropping the generic stuff (Smashing Ground) for specific stuff (Ally Salvo).
In this way, Closed Forest is closing off my Side Deck to more versatile options, but if it can help against the second most played deck, then it might just pay off.
All I have to do to accomplish this is drop $50-60 on Closed Forests...