WP_Post objects are classes that are stored in the database. It contains all the data of each specific class. Some of the objects within the WP_Post are post_author, post_date, post_title, and post_content.
The data the is contained in wp_post object is the variable that would be the numeric ID of whichever object is being called for. It could be the ID of the post_author of the ID of post_title.
On page load WP_Post queries the database and gets all the post data that is stored in a WP_Post object. The object then is used to display the data on the page. Without the WP_Post object, WordPress couldn't get the pull the data and display pages correctly.
A WP_Post object in Wordpress accounts for a piece of content such as a blog post, pages, or revisions. It is a standard class that stores key data such as title, author, ID, and content. It allows developers to easily manipulate data within themes or plugins. WP_Post objects help WordPress dynamically manage content through the post management system.