While Facebook touts this as a way to avoid spoilers for movies and TV shows in your timeline, it can also be used to cater what you see in your News Feed. Many people get their news from Facebook, but others don't want to constantly be inundated with their friends' and acquaintances' political opinions. This feature gives people the ability to take a break from politics (but, like any mute button, it also threatens to increase echo chamber effects.)
Regardless of how you use the Keyword Snooze feature, more control over what you see on Facebook and how you see it is always a good thing. While you can unfollow and mute specific people, this feature gives you more control across your entire News Feed, rather than focusing on the people behind the opinions (or spoilers).