My immediate reaction is that the problem with that approach is that it’s simply too expensive for the hiring company, in the same way that take-home programming challenges are too expensive for the applicants.

A company trying to hire engineers can easily give a take-home programming challenge to a dozen engineer applicants and take very little time analyzing the submissions. That’s pretty unfair. But it also feels a bit untenable for a senior engineer at a hiring company to have very deep investigations of each applicant’s work history.

Another problem is objectivity. If your company’s engineering hiring process relies heavily on a senior engineer’s subjective impression of an applicant, you’re going to have big problems with your own engineers’ biases, whether subconscious or not. Expect to hear a lot of evaluations like “well, the applicant did seem to have good knowledge and experience, but I just wasn’t impressed for some reason.”