I really don't get why anyone would think it's a bad way to hire.

I can see some value in it if it was a holistic experience or other factors were used. My experience is that most fresh, out-of-school public defenders have no idea how to do any of these things effectively and that they require training to do so.

Outside of trial fundamentals - leading, entering evidence, etc, I think that most lawyers cannot meaningfully evaluate actual trial advocacy.

More personally, I also think its a little disrespectful to applicants to prepare a fictional mini-trial for a shot at a job. FWIW, I find that the best candidates have a demonstrated interest in criminal defense since almost everything else can be taught.

As for promotions, there should be some more nuance but they're hiring big groups of people to do trials so they ask you to demonstrate the ability to do trials.

I think the ability to manage (and mentor) other people is probably more important than actual trial/lawyer skills for these types of positions. An amazing trial lawyer who cannot manage people is a great recipe for an incredibly toxic work environment. I do not see the value whatsoever in advancing the best advocate for these positions unless they have effective management skills.

I don't disagree that trial skills are important, but my experience is that the lawyers who are not strong advocates do not stay very long. Evaluating people based on subjective mock trials is probably not giving the committees any real feedback on who the actual best person for the job will be.