Following HTML5 Boilerplate, we add the description meta tag for search result snippets.
The major reason is as follows:
The quality of your snippet — the short text preview we display for each web result — can have a direct impact on the chances of your site being clicked (Google Webmaster Central Blog, Sep 27, 2007)
there are times when the content itself isn't the best source for a snippet. For instance, when someone searches for a publishing company for their book, the relevant homepages in the result set may contain only a few images describing the businesses and a logo, and maybe some links, none of which are particularly useful for a snippet. (Google Webmaster Central Blog, Jun 2, 2017)
Following HTML5 Boilerplate, we add the description meta tag for search result snippets.
The major reason is as follows: