A decentralized, non-censurable marketplace should, of course, offer products and services that are not available through the regulated Fiat markets.
This is still a real market gap, in the sense of real cryptoanarchists (yes, there should be in the flood of speculators, and in the end they are the ones who give the crypto currencies a value at all).
Cryptoanarchists (and only they can really do anything with free(!) crypto currencies) are urgently looking for a solution for an unregulated market.
The unregulated market is growing exponentially. There you only pay with crypto currencies.
Unfortunately, there are so far only centralized solutions that do not cover the full range of possibilities and are expensive and vulnerable.
Those who are not as stupid as the Byteball team and align themselves accordingly will have catapulted a clone of this project very quickly into the Top 10.
Can you name something that is not possible to buy with fiat currencies? Because, only thing that I can come up with is illegal stuff.
Blackbytes are not meant for illegal stuff, it's private because of privacy (privacy doesn't equal illegal). Cryptocurrency that has option to do public or private transactions are not 100% anonymous and not suitable for illegal stuff (use cash for that sh|t instead). It is just disaster waiting to happen for those who think they can use cryptocurrencies for illegal stuff because at some time in the future, somebody figures out how to do the analysis to link your public spendings with your private spendings, then it is just a matter of motivation for them. And we don't know if FBI/NSA can already do that or not, they have enough money to throw unlimited people at this problem (it also makes them much easier to do that because open-source).
This is same reason why Monero is not 100% anonymous because they were not anonymous from the beginning
https://medium.com/cryptics/monero-not-anonymous-at-all-113c3a14c816All cryptocurrencies are as private as they used to be (which we can know) and will be in the future (which we can't know).