Are meta descriptions really that important?

SEO plays a major part in the success of any site and the 1st thing people usually do is to create or change their meta tags e.g Meta Title, Meta Description, Meta Keywords etc. OK, I'm going to assume most of you already know what meta tags are, for the rest of you, head over to this page to find out more...
http://www.virtuacash.co.uk/2011/09/how-meta-tags-affect-search-rankings.html

In recent years the way Google operates has changed a lot and its becoming more and more apparent that the use of meta tags such as the Keywords tag have become basically useless.

One meta tag that people still claim to be ultra important is the Meta description tag. The meta description tag allows you to describe your page to search engines, letting them properly index your pages and create the visible description for your pages in search results.

The thing is, if we don't use the description meta Google will create the description for us automatically, usually from the first paragraph of our posts. But what most people miss is the fact that by using a Static meta description they could be causing their page to show up in less search results.

If you have no meta description tag Google generates a description for you, and usually they pull the most relevant info from a page to display in searches. OK, I don't think I'm explaining this great, so here's an example...

I do a search for 'why cats like milk', this is one of the results that appears in the search...

Do Cats really Like Milk?
http://ilikecats.kitty/cats
This post talks about why cats do or don't like milk, random but hey hum.
 
Above is an example of a search result where the meta description tag is in use. The author created this static description and this is what will show most times this page appears in searches, but the page is not showing in results for the search 'My Cheshire cat is fat. Is it the milk?' for eg.

Here is an example of a page with no meta description tag but a descriptive opening paragraph...

Do Cats Really Like Milk?
http://ilikecats.kitty/cats
Cats in nature don't usually drink milk after they have grown up, where would they get it from?...
My cat got sick from drinking milk and I'm worried...

As you can see Google has automatically created a description from the opening paragraph and not only that, it has also added relevant text from elsewhere in the page.

The beauty of the results/pages with no description is that Google will create the most relevant, keyword specific description for you, based on the whole page not just a static meta tag. This allows your page to show up in more varied search results.

Say I had a comment about Cheshire cats at the bottom of the page, if I type 'My Cheshire cat is fat. Is it the milk? in Google, you may see a result that looks like this..

Do Cats Really Like Milk?
http://ilikecats.kitty/cats
Cats in nature don't usually drink milk after they have grown up, where would they get it from?...
I have a fat chesire cat? What do i feed it...

Now the page is appearing in searches like 'My Cheshire cat is fat. Is it the milk', 'why do cats like milk', 'My fat Cheshire cat is sick from milk' etc. 

As you can see Google has pulled the first few lines from the post and has also added text that contains the keywords 'Fat Cheshire cat' from the comments on that page (although in some cases Google will do this for pages with tags to). If the page was using a static meta description tag, it may not appear in that search results for 'Fat Cheshire cat' because of the lack of keywords in the meta description.

So, are meta description tags important?

Well in my opinion Yes and no, more no. They seem to be more important to submission sites that use meta tags to auto fill info on forms but not so much in Google. If anything, I have found that by only using a meta description tag on the home page and not on other pages saves you time, minimises duplicate content warnings, and allows your pages to show up in more varied searches based on the pages content and relevant keywords rather than the meta description. (You may have to use 'if' and 'else' statements to achieve this e.g if homepage, show meta description, else show blank.)

I think the thing that drives the popularity of the meta description tag, is the fact that people love to keyword stuff (which Google will penalise you for) and the fact that every next guru tells you that you will fail without it.

What do you think? Am I chatting rubbish? Am I explaining this all wrong and need to write it up a bit better? or do you agree with me? Please let me know.