A couple of anecdotes:
I was able to hire an outstanding candidate simply because I got them through the process and extended them an offer. Our competition was a reasonably high-profile company in the area. In the end he joined us because after more than a week, the other company was unable to execute their paperwork to get an offer generated.
More recently, I saw a very big name West Coast company (think Google/Facebook/Uber) lose out on a great person because they had a third party do a reference check. In the time it took for that check to happen, the job seeker had lots of time to re-consider the offer and instead ended up working for a smaller company on the East Coast which kept in touch and was able to move blindingly fast.