Hi! In most WYSIWYG editors, like say Microsoft Word or Google Docs, whenever I want to add a paragraph, I simply place the cursor before or after and press enter a few times. I'd dare say that 100% of users are familiar with this functionality. So why is VisualEditor different and has an "Add paragraph" button appear between elements? This feature seems inconsistent with the way the rest of the VE works, and more importantly it seems to me like the main cause of differences between the rendered page and the VE surface.
Topic on VisualEditor/Feedback
It appears between floated block elements, a concept that doesn't exist in either Microsoft Word or Google Docs (because they're aping paper) but is fundamental to how HTML documents work.
If you are in a paragraph, you can just put the cursor somewhere and press return a few times, as you say.