Stack Exchange generally disapproves of tags that describe anything other than the content of a question. "Questions that were asked at a job interview" certainly fits that description.
However, there is another possibility that should be considered, though it should probably then be rejected. If the definition were something more like "For the sort of puzzles that get asked at job interviews" then it would be about puzzle content rather than puzzle origin.
The questions then would be (1) is there actually a reasonably well-defined class of "questions of the sort that might be asked at a job interview"?, (2) if so, is that class interesting enough to anyone to merit a tag (e.g., is it the sort of thing that might get searched for)?, and (3) if so, can the purposes that tag would serve be covered adequately by other tags?
To which I say: (1) I want to say no, but can't help feeling that there is a certain "feel" that these job-interview brainteasers tend to have; (2) probably not, but I can e.g. imagine someone who's just had a frustrating job interview finding the tag useful in tracking down a question equivalent to the one they got asked, or "job interview questions" being part of an FTC some time; (3) conditional on the tag being useful at all, it probably wouldn't be redundant with other tags.
All of which is very far from a ringing endorsement for keeping the tag around. I think it most likely wouldn't pay its way, and the fact that it hasn't been used much (only 12 puzzles!) seems like further evidence for that. So I'm inclined to say "let it burn" -- but the contrary arguments seem like they deserve airing, hence the blather above.
... Wait, I only find 7 puzzles tagged with it. Has someone begun the burnination already?