That actually sounds like a really good idea if it's possible.
It would be a blockchain-based neural network which people can sell training data to (in exchange for the underlying cryptocurrency) and which other people can use via an API to do pattern recognition on their own user data (by paying in the same cryptocurrency).
That sounda like an incredibly bad idea from incentives and exploitability alone. Machine learning on public data is bad enough /without/ paying people for it. At that point you'll get random garbage from a bot at best or deliberate attempts to turn your application as vulgar, violent, and racist as possible. Just look at the Twitch talking banana and the sheer level of effort to make it say racial slurs.
The redditors in /r/machinelearning have shot this idea down many times. A few common arguments:
1) It costs more and isn't as performant as tuned machines.
2) The training data is very valuable and shouldn't be shared on a blockchain and restricted to a closed network.
Maybe there is one advantage though. Crypto people have bought up all the GPU's.
1) There are many possible implementations. Right now the problem is that very few software engineers understand blockchain sufficiently so that they can design efficient solutions. There is always an overhead when coupling a service to a blockchain but it can be minimal if done correctly.
2) People get paid to provide quality training data... So yeah it's valuable but if there is a built-in financial incentive to share data with the system then people will do it. Also, other people could get paid to verify/curate the training data. The system just needs to setup the right incentives.
It would be a blockchain-based neural network which people can sell training data to (in exchange for the underlying cryptocurrency) and which other people can use via an API to do pattern recognition on their own user data (by paying in the same cryptocurrency).
It would be a decentralized, autonomous AI.