With Attu retaken, the US now posed a potential threat to Japan's Kurile Islands and Northern Territories that it would have to at least take into account, diverting its attention from other battle fronts.
In fact, the only combat which occurred on their equivalent of the Aleutians was a bloody firefight against a Russian force invading Shumshu Island in the northern Kuriles in August 1945. Arguably, that garrison was put there in anticipation of an American invasion, so there was at least some diversion value. But probably not much.
Interestingly, the gulf stream is active miles above these miserable weather islands and transpacific flights still most commonly take these routes. Once in a great while, these flights even use them for emergency landings as I believe a China based commercial flight did at the U.S. base in Shemya some years ago.