Post Formats are visually filtering the information for you. Every post format looks different according to their importance.
For example Asides have an inverted color scheme because what’s written in an Aside is a must to know.
Quotes have distinctive backgrounds and typography because a quote is good to be known.
Links are kept simple because they are just a pointer to further reading, they are not as important to be remembered.
When scrolling through the posts / feed the different post format designs can let you spot what needs to be learnt, and, check if you still know what you’ve been already learnt.
This feature is in the same way useful for filtering information and reasoning about.