I use it to hide the things that I know I'll never be interested in engaging with here (politics, mostly.) Also, when the site gets really focused on something I have limited interest in, such as crypto in recent history and LLMs now.
It helps declutter the site.
Another thought: It would be very cool if I could auto-hide things based on where the link goes. I'll never want to click on a twitter or youtube link, for instance, and it would be convenient if I could just make them not appear.