Kinnikuman: Yomikiri Kassakusen is basically a collection of one shots and 1 two shot short stories giving insight on some events that weren't covered in the manga nor anime like how Broken Jr began to respect Ramenman and how the Blood Brigade came into existence. For the most part they are stories that hit you emotionally and serious instead of focusing on comedy and thoughtout wrestling fights Kinnikuman is known for. But the story about Benkiman may be intended to be comedic as it makes fun by explaining something utterly stupid in such a serious manner like how Benkiman helped a child by letting it shit onhim. Something that suppose to come off as caring but actually comes off as hilarious simply because its a living being shaped like an old toilet.
If you are a Kinnikuman fan, you will certainly enjoy at least some of the stories you read.