Sloooow AI.
The Blockchain is working like a market, and its "intelligence" depends on market participants, which are humans.
That means the blockchain is as intelligent as it participants, but that is not AI.
An AI could be a market participant using the blockchain to trade/communicate/store informations/signals.
when it emerges it will take part and coordinate the actions.
no, that is a modern myth, AI doesn't emerge just from nowhere