I have found this to be quite useful and do hope to see it pull from more social platforms.
It helps the content creator understand how their content is being shared with the outside world. Not everyone tags you when you do so or you have a different social handle across multiple platforms. This also allows the content creator or someone who reads comments the opportunity to engage with that Tweet as well if they like.
It can also help create some positive reinforcement that people are taking the time to share your content with their followers elsewhere.
I don’t feel like I have to both leave a comment and take the time to share something on say Twitter. I can just do one.
I could see one day people wanting an opt-out option or say a global blacklist that has “useful” bots in it. For now they can just use the mute button.