Why should beginners learn escapes before attacks?

If you are on top mount and want to go for an armbar, but you know that if you lose it you will end up in a bad position you cannot escape, you will never attempt that armbar. You will just hold positions out of fear. But if you have confidence that you can escape any bad position or submission, you will freely attack knowing that even if you fail, you can escape and go right back into attacking.