“Valve has announced it’s retiring the Video section from the Steam store. You’ll keep any videos you’ve already purchased from Steam, though, so you don’t have to worry about losing anything you’ve bought.”

https://www.gamespot.com/articles/valve-is-removing-steam-video-section-retiring-non/1100-6465133/

“In reviewing what Steam users actually watch, it became clear we should focus our effort on offering content that is either directly related to gaming or, is accessory content for games or software sold on Steam,” Valve wrote in a blog post. “As part of this refocus, we have retired the Video section of the Steam Store menu with an expectation that video content is discovered via the associated game or software store page, or through search, user tags, recommendations, etc.”

Valve will retire “a number of non-gaming videos” which will no longer be available for purchase, you’ll still have access to these videos you’ve bought before, otherwise they will be gone from Steam Store.