Sometimes, while interviewing for multiple jobs, the window to accept an offer for job A ends before you receive an offer for (preferable) job B. So you accept job A as a hedge, and then immediately rescind job A if you get the offer for job B.
And there's nothing wrong with that, since if you view A and B as actors, they're both (because they're inhuman corporations) psychopathic monsters who will fuck you over in an instant