As a bit of an aside grant reviews were apparently brought in initially to help scientists avoid working on bad areas. The idea was that everyone would get funded who put up a reasonable grant and they just wanted to help screen out the bad ideas so people didn’t waste their time.
We have since twisted this into the current system where we try to determine which of the top few percent of grants are the best. Of course the whole ranking process is so noisy that it is little better than chance for anyone in the top 25%.
A much better system would be to rank the grants as worth funding or not and then put all those worth funding into a lottery to choose who gets funded. At least this way even the losers would know they were on the right track and they were just unlucky. It would save an enormous amount of grantmanship and other activities that are the antithesis of everything science should be about.