Spam Comments What's The Point?

Are the people behind the Spam Blog Comments that are just full of random words strung together that make no sense and full of random links stupid? Do they actually think that Blog Authors are actually going to approve these useless Comments that are

A) Don't make any sense and are full of Links.
B) Mostly off topic to the Post that they have commented on.

I can't decide if Spam Comments are by other Bloggers that haven't got as big of a following as the Blog that they Spam in hope of

A) Getting Spammed Blog down ranked by search engines due to Spam Comments.

B) Idiots that have nothing better to do with their time than leave Spam Comments on Blogs.

or Bots that just trawl the Net Spamming every single Blog there is.

But I thank god that I decided to use wordpress.com when I started Blogging as the Akismet Spam filter built into WordPress does a pretty good job of filtering out Spam Comments even though the odd one or two Spam Comments slip through the filter and every now and again I get the occasional off topic Comment.

But that still doesn't answer my question about What's the point of Spam Comments as all Spam Comments do is waste the time of Blog Authors who have to go through the Comments and delete all Spam, and that takes time away from them producing great content that people actually want to read, and it's a waste of Spam Commenter's time as none of the Spam Comments are actually going to get Approved by Blog Authors.

Rant Over

Roland