Yes blog commeting is good in SEO but it should be on relevant blogs.

Blog commenting is another great strategy of SEO its generate huge traffic and increase website visibility in SERP

how my friend?

where I can find blog with comment do follow?

commenting on a blog with your domain URL...

search blogs related your site then submit comments

Blog comments are used for creating backlinks

Blog commenting is another great off page Seo strategy of promoting your website through content

It is also a type of backlinks you post a comment as normal and add your keyword as anchor text in the comment.

blog comments are both nofollow or dofollow. you can search for the term 'commentluv' in google and can find out blogs which are using commentluv. If you comment on such blogs with your domain url then you get a dofollow link.

Blog commenting is another great off page SEO strategy best way to promote your content or keyword in between target audience

How blog commenting is beneficial for better page ranking?

Blog commenting is an essential procedure for interaction between blogs, bloggers and blog readers.
It is an action wherein visitors or blog readers leave a comment to a blog post or article, reply to readers' comments, or the author himself answers or replies to visitors questions and comments.

Blog commenting is adding review/comment in published article on website. Most of site allow reference links insertion with comment. This SEO off page activities consider as quality links building for individual web page or website.