Well, I thought the problem being solved was the centralization of exchanges.
This is the tagline from Symbiont: Symbiont is building the first issuance and trading platform for smart securities on blockchain technology
I gather from that they are going to allow businesses to issue and trade Counterparty based tokens on Bitcoin and that businesses can create smart contracts to facilitate these trades or whatever it is that they want to do. I don't think that the market Symbiont is going after cares if something is decentralized or not because everything those businesses are and associate with is
not decentralized. I think they just want cost savings and stuff. Again, I'm not sure either and I would also like more clarity. But, as Robby said in a recent interview, Symbiont won't even be disclosing the market they are targeting, let alone what the specific model is. It is nice, as an investor in XCP, that Symbiont feels they have to be that tight lipped about the model in order to retain their first mover advantage.
EDIT: Also worth noting is that while Counterparty is open source and can facilitate a bunch of decentralized stuff, businesses that are for profit, like Symbiont, can and will build centralized solutions on the technology that solve real world problems while also increasing the value of the Counterparty platform and the XCP token, just like Bitcoin