As Sara told Ava, she spent years training while blindfolded for the League of Assassins, and she barely needed to be led around in “Ship Broken.”
Honestly, if any character was going to be struck blind and then return to business as usual, Sara was the best bet despite her previous lack of superpowers.
As for fighting, Constantine reminded her that her ears work even if her eyes don’t, and she got to show off her skills even if she couldn’t see her opponent.