I somewhat agree with you, but I think it's very important to distinguish between the two meanings, because different points on the continuum of correctness cause you to come to completely opposite conclusions about the nature of the universe. A bit of quantity leads to a totally different quality. In other words, truth and usefulness are continua, but they are two different and orthogonal continua, and going right on one may mean going left on the other.
My view of the universe is going to be totally different if Newtonian mechanics is the "truth", versus if something like quantum mechanics is the "truth." The former depicts a totally deterministic and knowable-in-principle clockwork universe, whereas the latter has randomness and ignorance that cannot be removed even in principle. Quantum mechanics may not be the whole truth, but it's certainly so different that it shows earlier approaches to be not just incomplete but totally incorrect about their fundamental assumptions, even if they can be used to make useful predictions. Quantum mechanics isn't just more useful, it's more true, whereas Newtonian mechanics might be more useful than some other theory, but actually less true in some sense.
My view of the universe is going to be totally different if Newtonian mechanics is the "truth", versus if something like quantum mechanics is the "truth." The former depicts a totally deterministic and knowable-in-principle clockwork universe, whereas the latter has randomness and ignorance that cannot be removed even in principle. Quantum mechanics may not be the whole truth, but it's certainly so different that it shows earlier approaches to be not just incomplete but totally incorrect about their fundamental assumptions, even if they can be used to make useful predictions. Quantum mechanics isn't just more useful, it's more true, whereas Newtonian mechanics might be more useful than some other theory, but actually less true in some sense.