As
@funnyhat said, they got it back after the war, and its loss didn't really change much during the war. It might make things easier for British privateers but French shipping was already in a tailspin well before the end of the war, so that hardly matters. On the other hand, Byng's fate has sometimes been said to have influenced subsequent British captains who learned the lesson that aggressiveness and risk-taking were to be rewarded above all, an attitude which was generally (if not always) advantageous to the Royal Navy. If you believe that, then the example of Byng probably mattered more to history than the actual material effect of his defeat.
As for Byng himself, he certainly deserves a pardon. Newcastle failed to prepare the British navy for war, failed to adequately garrison Menorca or Gibraltar, failed to keep a sufficient fleet in the Mediterranean to defend those posts, failed to heed repeated warnings that the French were preparing for action in the Mediterranean, failed to provide adequate ships, crew, or ground forces for the expedition (Byng had to press
regular infantry into crew service because his ships were so undermanned), and then lied to conceal his negligence, releasing an edited version of Byng's report with the obvious intent of shifting as much blame onto the admiral as possible so as to save his own skin. By all rights it should have been Newcastle facing a marine firing squad on the deck of the
Monarch. Perhaps Byng was not as audacious or aggressive as he should have been, but IIRC the council of war he held with his captains unanimously supported his decisions at the time, and he was purposefully trying to follow the rules of action (as
not following these rules closely had gotten Admiral Matthews cashiered after the Battle of Toulon). Maybe he should have been sacked, but he didn't deserve death.
