Unfortunately, thanks to the efforts of USS Johnston and friends, her sinking turned out to be for nothing.
Well, no one neither the Americans and the Japanese would have thought that three destroyers, four destroyer escorts and six jeep carriers would put up a fight and fend off the full force of Centre Force. Hell, even the commander of Taffy 3, Rear Admiral Clifton Sprague expected that he would be in the water by the time Centre Force turned tail.
Unfortunately, thanks to the efforts of USS Johnston and friends, her sinking turned out to be for nothing.
Samar was meaningless actually, well, beyond further depleting the already crushed Japanese fleet anyway. People that act like it mattered and that if Center Force continued they could have accomplished something haven't researched the topic at all. The facts are simple.
-The operation had already failed. It took too long to launch, by the time the ships were approaching the gulf the transports had unloaded and most were already gone having been sent away when the enemy approach was detected. At most they could have ineffectually bombarded the beachhead briefly, maybe sunk a few straggler then be annihilated. -They never would have made it that far anyway, by the time Samar was over (assuming they actually did press on and destroy most of Taffy 3) the force had been brutally attritioned; it was down to four BBs, two heavy and two (weak) light cruisers, and about nine to ten DD. US Forces on hand in the Gulf meanwhile consisted of six BBs (equal or better to any of the Japanese ships beside Yamato for a defensive action), eight large cruisers, nearly sixty DD in various divisions, and the remaining Taffy carrier groups which had not been engaged -The first Fast Carriers would also likely be in range and deploying long distance strikes by the time any battle to try and force the Gulf began. The entire fast battle line of modern BB is also racing south by this point. If Center Force regroups and then dives for the Gulf they either A: just flat out loose in a battle with the defensive forces. B: get so bogged down in a running action they're swamped by increasingly dense carrier air and possibly even the returning fast battleship, or C: they eventually break off when they realize that heavy surface units are in the way, but find the fast battleships and escorts now blocking their exit.
They may sink another few US ships in this scuffle, but near total annihilation of their force in the vein of Nishimura for zero useful result is the probable outcome. The whole 'lost cause' mythologizing of this battle isn't really based on facts. It was a suicide mission that was too late in coming and had already failed by the time it was launched. Every aspect of it was meaningless cause it never actually had any chance of success.