I have a slightly different take on this. Given the huge number of applications each AO is initially responsible for, just as a function of time and effort management, I suspect some app’s are tossed based purely on the applicant not hitting some objective thresholds in grades and test scores. There are probably also a very limited number of applications that go to the admit pile with a relative cursory reading of much of the file based on some combination of objective stat’s, extremely strong hooks (e.g. athletic recruit, scion of major donor, etc…) and/or truly unique and outstanding accomplishments. This leaves us with the vast number of academically qualified applicants, maybe 15-20 thousand plus, where the hard choices are made. Given the statistics we can see from other highly competitive schools that have broken out acceptance rates by test scores and HS record (e.g. https://admission.stanford.edu/apply/selection/profile16.html; https://www.brown.edu/admission/undergraduate/explore/admission-facts – the Brown stats are particularly granular), we see that higher objective stat’s students are admitted at a materially higher rate, in other words the system is not one where once you hit the minimum hurdle, all applicants are “equal”. While there is going to be some level of correlation between high stat’s candidates who get better LoR’s and write better essays, the differences in acceptance rates and percent of matriculates suggests higher stat candidates have an advantage.
So now we have to speculate as to why a “1450” candidate gets in when “1540” candidates do not assuming similar HS grades/rigor. Obviously it is down to the LoR’s, essays and EC’s (putting aside remaining hooks like URM, first gen, legacy etc…). Of these 3 things, the only one that is fully within the control of the applicant at the time of the application are the essays. So my advice would be, the further down the objective stat’s range you are, the more you have to write an essay that will grab an AO’s attention, especially in the first paragraph. So if you are well below the median in objective stat’s, I say “go big or go home” in your essay. If you are above the median, a more conservative approach is probably warranted. Obviously write the best essay that you can to advocate yourself and your fit with the school, but you might want to avoid going out on limbs that may get attention, but not necessarily in a good way.