I think it is a toss-up: it gives the Central Powers a deeply needed morale boost and puts them farther south and west. There would probably be another strategic-level victory needed to win the war, probably near Ependay, Meaux, or Chateau-Thierrey. What it might do is open the door for a negotiated peace with the Central Powers keeping their Eastern victories and the Western Front becoming the bugbear. With the Second battle of the Piave River having already happened, it won't causs the collapse of Italy, but it will reinforce Austro-Hungarian morale somewhat and may cause the Piave to become a frontier. Belgium likely remains free, Luxembourg likely German along with Alsace-Lorraine, and Germany *may* agree to some sort of token reparations in exchange. UK is totally broke, France may go into open revolt, and perhaps AH still shatters like glass.