This is cool, but it's nothing new. Unroll came out months ago. In fact, the focus of the product is more as a newsletter aggregator, which is and of itself a cool concept. I've been using it, and it works to a certain extent. It's not perfect, but it's a nice idea.

Also, you might want to check out Safe Shepherd (née MelonCard), which is similar.

https://safeshepherd.com/

How can you unsubscribe from spam? If you didn't subscribe to it in the first place then no amount of pleading will make them stop and if you did subscribe then it's not spam. The only things that help is aggressive filtering and and a good email client. Everything else is in the hands of sysadmins.

I do not see the purported usefulness of this.