Usefulness can be a very subjective thing. Plenty of string theorists find it useful. Some like to go on about how the math is all so usefully aesthetic compare

Usefulness can be a very subjective thing. Plenty of string theorists find it useful. Some like to go on about how the math is all so usefully aesthetic compared to alternatives. It looks nice so it feels nice to work with, there's a usefulness there. Others talk about how String Theory has been very useful in finding new questions. Sure, it has been having a rough go at finding testable, predictable answers to all the new questions, but sometimes it is still very useful just to have interesting questions to ask the next theory, because maybe that will have useful answers. (The scientific process starts from questions, hypotheses, of course.) I won't defend astrology's usefulness, but there's certainly centuries of subjective feelings about the subject to find in many libraries, if you care to. Usefulness as a subjective quality is orthogonal to any objective criticisms about the usefulness as a model.