It was a US Pyrrhic victory and a strategic defeat. US would have been better off never fighting for the island, and never using it. An unnecessary battle that the Marine commander tasked with carrying it out opposed, and was carried out not of real strategic necessity but in service of perceived US Army Air Force an Marine Corps bureaucratic interests. It was projected to cost 600 killed but ended up costing in total casualties more than what the Japanese lost, and diverted badly needed forces from the more important, and more sensible Okinawa landing. Then yet more resources were lost as military pretended it was a useful gain to justify the senseless loss of life.
Source: Tales of the American Empire