Another reason for the creation of this type of content is to exploit the existence of the content networks detailed in the infographic / slide.
Slideshare, YouTube, Lists etc are all destination search sites. People go there to find content. Creating compelling content on these platforms ensures you get higher search ranking (a ranking that is independent of Google).
Given to use these platforms you need to create content in a specific format, it makes sense that people will experiment with repurposing content, ideas and formats from other platforms.