I left a comment on your other post that gave a few reasons they will benefit the chain. I will outline one more here.

Many feel that crypto will replace fiat. I don't see it as it currently stands as the barometer for the value of crypto is in fiat, there are very limited uses for real life purchasing with crypto. The masses are wary of crypto, and if there is ever to be mass adoption it will come from a model such as this that allows for Both to be used on the same platform. This will allow crypto to be like a house currency, similar to what Binance does with their coin. IF, and this is the heart of the matter, if they are able to gain buyers and sellers (I mentioned in my other comment why this may happen) who are not crypto users, this could be an important doorway that allows them to jump in without the headaches of using an exchange. That is a huge impediment for many not willing to use crypto.

As Steemit was my doorway into crypto, this endeavor could be the doorway for many more, as many don't wish to blog, but many do wish to buy and sell. I mentioned in my other comment that Ebay was ruined as a peer to peer site by Meg Whitman and John Donahoe. There are many sellers who long for something to replace them that is truly peer to peer.

I understand that you are Steem focused. I respect you (which is not easy to come by with me), and hope that you will consider the dynamics I pointed out. I don't get excited over most of the projects announced here, but this one excites me to no end, despite my not having any power to delegate to them. If they are successful, it will be part of their history that it was with Steem backing they pull this off.