The term “blockchain” is often overused, and can have different meanings in different contexts. Blockchain technology has 3 major components that together really make it an innovation. Strictly speaking, a blockchain is just a data structure similar to a linked list. Blocks of data reference their previous block by including their digital fingerprint or hash in their block of data. If a previous block is modified, then all the following hashes will be different and it is easy to detect if the data has been tampered with. Even more importantly, is that this establishes an order to when events took place, in the case of Bitcoin, these events are transactions. The final piece is a consensus mechanism that allows participants on a public distributed network to all agree on a chain of blocks.
A consensus mechanism on the other hand extends the blockchain data structure by providing rules that enforce how blocks are accepted by the network as a whole. For example, with the proof-of-work consensus, there is an agreed upon amount of work that must be done before a block is accepted as valid. The lower the threshold, the more work must have been done to calculate the block hash. Providing a valid block hash becomes a proof-of-work. This can make it much more difficult to modify past blocks, as the same amount of work must be done in order for the network to accept it as valid, thus distributed consensus can be achieved. This is why “blockchain technology” was invented, to achieve distributed consensus without relying on a third party. “Blockchain technology” is not really that interesting without the proof-of-work component and so it depends on what your definition of “blockchain technology” happens to be.
In conclusion, by this definition of blockchain, it doesn't make sense to use blockchain in a centralised environment.
