Is a strong Cover Letter with the Resume an important step in getting that “Second Look” from Recruiters Online?

Again being in the recruiting business and high volume recruiting business don't have time to look at the coverlet terms. Focus on the resume and networking so that you get referred to a role. That is where 70% of people at least get a look and possibly an interview

You have to know your audience, industry and company. Cover letters may work well for a smaller company. When I am looking through thousands of resumes for multiple roles I am looking for the meat and the potatoes so I can get candidates over to Hiring Manager for review

Interesting thing is USA Jobs won't allow for cover letters which are typically a bunch of hot air. Prior to USA Jobs, we had the HR side strip the package of cover letters as they were not part of the required submissions that are valid to review.
That said, on the outside, a decent cover letter can't harm, but isn't likely to do much good either. People still do them because they think is slightly better than 50/50. Bottom line, if you're anal about cover letters, your mind is in the wrong place.