Although a lovingly crafted CV with fancy formatting and a recent headshot might look great, that isn’t what most employers are looking for. They want to know about your experience, not your design skills (unless you’re applying for a design position, of course). You don’t want your formatting to distract from your accomplishments.
When a job is especially competitive, employers simply don’t have the time to give each and every CV an in-depth analysis. As a result, they’re looking for reasons to throw out some CV and narrow the talent pool. If your potential employer is a stickler for spelling or grammar and you make a small mistake, it could cost you the job.