Because when threatened you arent supposed to waste the next 10 turns running your bishop away, you are supposed to trade with the knight.
Removing both knights asap with your bishops opens up the whole centre for you to take and also kills the enemies fork and support push down the sides.
Its purely for advancing up the centre, if you want to go for the sides then you need to preserve your bishops and knights. For middle you need knights and pawns and a quick dispatch of enemy knights.
Now if somehow you trade both your bishops for the enemy knights and somehow still lose the centre .... I don't even think thats possible like bruh must be 50 elo to manage that.
If you're playing as black and trying carro kann defense, enemy knights will hugely **** you up if you can't get rid of them, as happened in a recent game of mine.
Importantly you dont take the knight right away, only after the pin is broken or you are threatened with A6 / H6. Because the king side one is stuck anyway so you use your moves developing the centre. If the queen side one blunders and moves you get a queen, which tbh happens rarely but you never know.
Ok, I understand that Bb5 threatens the c6 knight, indirectly dominating the d4 and e5 squares to facilitate a c3 and d4 push, but in the first 7 moves Black usually expels this b5 bishop with a6 + b5 (causing a weakness on Black's queenside), my question is: What did White manage to gain in these 7 moves? Why does White spend all these moves for the bishop to stay on the same diagonal as the Italian's bishop?
I can't understand this, the only reason for me to choose to play Italian or Ruy Lopez is because I can escape some lines, as the Italian I know I'll probably face a Guioco Piano (Bc5) or Fried Liver (Nf6), while in Ruy Lopez There are more variations, but many are very similar.