Yeah for me it still works. However if and only if you link to relevant blog niche sites.

Yes, Blog Commenting is the most affecting strategy to rank a site. be that as it may, be-cautious remarking must be significant and successful.

Yes Blog commenting is very helpful for you website ranking. In below here I am going to share some benefits of blog commenting...

Benefit of blog commeting
Build relationships with blogger
Good amount of traffic
Quality backlinks
Improvement in Search engine ranking

I see blog comments as traffic generating technique, not really a SEO technique, because:
Most blog owners use Nofollow for external link. Especially, the quality sites that have good engaging traffic, never give dofollow links
It is really tough to get good (desired) SEO link juice to your site since well-formed comment to benefit your site is never approved
To get most out of comments, you really need unique contents. It becomes tough when you try to do that for each blog

But, I'd not call it a waste of time, because it has good potential to bring traffic to your site. Many sites that engages your target audience, you should be active on those sites. And the best way to ensure that is through blog commenting.

Blog commenting is very important for SEO. It helps in create good backlinks of your site.
But you have to very carefully while doing blog commenting because admin do not allow fake or spam comments. So just be really and commenting must be related to the topic.

Of Course, Blog Commenting is the major part in SEO. It prove the strong backlins.