It seems the benefit would be one sided - that initial 100 -> 10 (ATS/interview/coin-flip) filtering processes would as usual have a large percentage of both false positive and false negatives.

The false negatives suck for both candidate and hiring company who have accidentally rejected someone they would have like to have hired.

The benefit of the "provisional employment" process would be that even if it doesn't help avoid the false negatives, it would weed out the false positives so that the company at least ends up hiring people who are qualified and a good fit (even though due to the false negatives they may have rejected even better candidates).