I'm not sure why this particular idiosyncratic thing attracts so much mystery, but the answer is that there are long essays about the recipes because people like them.
I assumed the long essays were for SEO (inflates the amount of cooking-related keywords). Which would make it kind of ironic that another Google product is now stripping the SEO content back out.
I actually think the issue is that the long essay provides more space to put advertising alongside or interrupting the flow.