This likely will only apply to people who aren't interested in the public back and forth. Like say X has 50 or so twitter people they follow (possibly mostly their friends), but aren't interested in randos showing up, they would then use that feature.
But if you are someone that particularly thrives on getting reactions for the sake of itself or for the sake of popularity, you ain't going to use that feature. Basically it makes no sense for anyone who isn't trying to use Twitter in a more private and personal way. You will just stick to blocking individual accounts.