The cables aren't critical, though. They're nice to have for peacetime, but given it hasn't happened yet it's clear each nation is able to at least function without them. In a war, there'll be bigger concerns than "everyone turned on their AC in Israel and we'd like to buy energy from Greece".
One of the biggest goals of the many undersea cable projects around the world is to enable much higher dependence on unreliable renewable power. They may not be critical yet. But they will be.
