It is very good for SEO (Search Engine Optimisation) . Actually, why we are adding meta tags is to tell search engines what that page is all about... but, using same meta tags to all of your blog posts lessens the search engine rankings and traffic little bit.

But, if you add different unique meta tags to different Blog posts, it makes the search engines to know more about your individual blog posts and make them crawl and index your pages better and it also improves your Search engine rankings for sure

For this to happen, you have to add some pieces of codes to the template.

First Sign in to Blogger dashboard » Layout » Edit html

and find this line