These guys make a good argument that you can do just as much good or more by working a conventional job and donating money to nonprofits than by working for a nonprofit directly:
That video assumes that nonprofit jobs aren't high-paying, but that's not always the case. KA, for instance, pays competitively. If you can both have a high-paying career that enables you to donate while also using your skills to help advance causes you care about (especially if the skills in question are skills that many or most people don't have), then by the reasoning in the video, that's better than either option they present.