GP does support post formats.
Currently, the different between each format isn’t massive, but if you add test posts for each you should be able to see the difference.
Standard is just a regular post.
Aside doesn’t display a title or link to a post – it’s just a quick thought.
Image/Video/Quote shows the full post with HTML.
Link takes the first link from the post and makes the post title link to that link.
Status only shows the text – no title or meta.
You can see some of them here: http://demo.generatepress.com/