Value
to whom?
Suppose you work for me. I pay you because your work has value to me. Congratulations: you aren't doing something no one cares about. But your work for me could be (1) finding a cure for cancer (hugely valuable to everyone if it works out), or (2) making my brand of smartphone 0.1% better than its rivals (hugely valuable to me, positive value to others but maybe not much), or (3) writing effective advertisements that persuade people to by my product rather than a rival's which is actually slightly better for their needs (hugely valuable to me, negative net value to the world), or (4) assassinating people whose politics I don't like (valuable to me, presumably, but probably not so good overall).
If doing something that someone values is enough for you, then indeed getting paid is (more or less) a guarantee of that, and getting paid a lot indicates that you're doing something someone values a lot. But they might value it merely because you're sending money to them that would otherwise have gone to someone else. They might value it merely because you're creating value for them by destroying 10x as much value for others. If you care about doing something that's valuable overall then being well paid is no guarantee whatsoever of that.
(You might hope that if your employer is making money then someone values what they do, and so on recursively, with the process necessarily bottoming out at people doing things that are actually useful overall. Alas, that isn't guaranteed either; or, more precisely, there is no guarantee of any connection between what anyone is doing and its overall value.)