Blog commenting helps your SEO as an indirect, gateway activity. Yep; comments are No Follow. But commenting genuinely on blogs for weeks or months helps you make friends with bloggers in your niche. These bloggers interview or mention you on their websites (backlink juice) or invite you to guest post on their sites (backlink juice.) So blog commenting is an effective activity for getting your SEO game tight in indirect fashion.
Many Warriors do not see beyond today. Or, cannot see the benefits of actually befriending human beings, being hellbent on seeing an instant result or direct benefit from any one action. More than ever though, Google is forcing you to help folks and build friendships to rank on page 1. Guys like Neil Patel kill it on Google because they dot all the i's and cross all the t's SEO-wise with smaller details but offer immense value and build friendships. He featured me at least 3 times on his blog that I know of, and blog commenting was a prime strategy that helped me land backlinks on his iconic blog, John Chow's blog, Forbes, Fox News, Entrepreneur, Virgin and Positively Positive, let alone the 1000 plus guest posts I've place.
Had to share because so many new bloggers and marketers are confused about how blog commenting works SEO-wise. Also because this is an awesome way for new bloggers and marketers to make an impact in their early days, before guest posting and feature opportunities avail themselves. No barriers to entry save staying out of spam folders.