I think one of the reasons decentralisation makes better decisions, is that every node has equal say in the decision.
Whereas a centralised system may not ignore a lot of the nodes when making a decision.
Whereas a centralised system may not ignore a lot of the nodes when making a decision.
The same logic applies to less decentralized systems like NEO that have a predefined set of voting nodes. Less nodes, means that we need less effort to achieve consensus, hence higher performance.
So the question is: in what use cases truly decentralized systems cannot be replaced with not so decentralized systems?
However, since all the power is concentrated to one "source of truth", it can lead to unfair decisions for the rest of the network.
Decentralized systems are ideal went you want to ensure there's fair decisions for the whole network. It's much more complicated to build, but worth it in some cases eg; crypto currencies, governments etc.
Also it's not strictly a black and white categorization, systems can have levels of decentralization; eg: the internet