Are writing things that allow BYU to sniff out that the kids themselves don't believe in the mission of BYU? Highly doubt it.
I'm not saying ditch the essays altogether. I'm saying that if the admissions committee is giving any more than minimal weight to essays in their admissions decisions, they are dumb. Its the easiest thing to fabricate, and therefore is likely the least representative of the student's qualifications to attend school there.