Their customers were hiring something like 10k jobs worldwide annually, which means 500k+ applications to go through.
AI was used for the first filter to get a person through to later rounds.
It makes sense at that scale, and not for "hiring" but just to make decisions as to who gets to the next round.
The alternative is that you end up having to hire so many people to go through the applicants and then those people get bored of asking the same initial questions again and again.
I remember hearing an anecdote, back in the days of paper resumes, that hiring managers would take the huge stack of resumes they got, divide them in half and throw half in the bin. That half would be considered unlucky, and you don't want to hire unlucky people.
But seriously, with the number of job applicants, for certain positions, what are the alternatives to getting AI to help?