In brief: Many developers cover their game's key art on Steam with award logos, scores, and other accolades in the hope of attracting more buyers. Not everyone appreciates it, and that's why Valve is banning the practice as of this September 1.
Valve writes that more text, award logos, and even review scores are being included in games' graphical asset images. The company says this can cause several issues for users, from the logos ending up so small that they can't tell what a game's name is to the pictures themselves becoming cluttered and hard to read.
There are other problems, too. Valve warns of review scores that are no longer accurate or come from a less-than-reputable publication. Moreover, most of the text is presented in English. While English is the most spoken language (36%) among the platform's users, there are still plenty who won't understand the words.
It's noted that if someone does want to know a game's reviews and awards, they can just visit the store page where they'll see official/user reviews and all the award logos.
Other rules Valve is implementing on September 1 include banning discount marketing, so no boasting about sales or money off in the images. It will also start disallowing text or imagery promoting a different product, such as sequels or games in a franchise, and all other miscellaneous text is also being banned.
There are some exceptions to the rules when it comes to large updates and seasonal events. But developers must use artwork overrides---separate layers that sit on top of the existing image---for these promotions, and the text must only describe a major update, new seasonal event, battle pass, DLC, or similar new content.
A quick look through Steam shows the changes are going to impact a lot of games: Hades' cover is packed with all the awards it's won; half of Wasteland 3's main image (top) is made up of its review scores, much like Pathfinder: Wrath of the Righteous (above), Lemnis Gate, and NieR Replicant.
While popular, well-known games are unlikely to be affected by removing their images' award logos and scores, we'll have to wait and see if the change impacts smaller, lesser-known titles to any significant degree.