Slides and blog posts do not get more citations than journal papers.

You've given non-representative or invalid examples:

1. For the paper following a blog post: It's the ArXiv paper that has the citations, not the blog post.
2. For Andrew Ng's course notes: Sometimes, professors arrange for a course-note-taking semesterial project which is intended to eventually produce a textbook. When this happens, notes are taken much more seriously, beefed up a lot of after class, go through round(s) of review by the professor or peer students, follow strict formatting guidelines etc. This is nothing like lecture slides. Also, textbooks != papers.
3. The "Notes on Convolutional Neural Networks" document is not a deck of lecture slides nor a blog post. The fact that it has "notes" in the title does not mean it is just some scribbles jotted down - it looks serious.

... so your premise is wrong.

Slides and blog posts do not get more citations than journal papers.

You've given non-representative or invalid examples:

1. For the paper following a blog post: It's the ArXiv paper that has the citations, not the blog post.
2. For Andrew Ng's course notes: Sometimes, professors arrange for a course-note-taking semesterial project which is intended to eventually produce a textbook. When this happens, notes are taken much more seriously, beefed up a lot of after class, go through round(s) of review by the professor or peer students, follow strict formatting guidelines etc. This is nothing like lecture slides. Also, textbooks != papers.
3. The "Notes on Convolutional Neural Networks" document is not a deck of lecture slides nor a blog post. The fact that it has "notes" in the title does not mean it is just some scribbles jotted down - it looks serious.

... so your premise is unsubstantiated. Actually, it's incorrect as far as a I know.

You've given non-representative or invalid examples:

1. For the paper following a blog post: It's the ArXiv paper that has the citations, not the blog post.
2. For Andrew Ng's course notes: Sometimes, professors arrange for a course-note-taking semesterial project which is intended to eventually produce a textbook. When this happens, notes are taken much more seriously, beefed up a lot of after class, go through round(s) of review by the professor or peer students, follow strict formatting guidelines etc. This is nothing like lecture slides. Also, textbooks != papers.
3. The "Notens on CNN's" document is not a deck of lecture slides nor a blog post. The fact that it has "notes" in the title does not mean it is just some scribbles jotted down - it looks serious.

... so your premise is wrong.

Slides and blog posts do not get more citations than journal papers.

You've given non-representative or invalid examples:

1. For the paper following a blog post: It's the ArXiv paper that has the citations, not the blog post.
2. For Andrew Ng's course notes: Sometimes, professors arrange for a course-note-taking semesterial project which is intended to eventually produce a textbook. When this happens, notes are taken much more seriously, beefed up a lot of after class, go through round(s) of review by the professor or peer students, follow strict formatting guidelines etc. This is nothing like lecture slides. Also, textbooks != papers.
3. The "Notes on Convolutional Neural Networks" document is not a deck of lecture slides nor a blog post. The fact that it has "notes" in the title does not mean it is just some scribbles jotted down - it looks serious.

... so your premise is wrong.