Blockchain has become the basis of a lot of transactions. It's data storage over the usual database methods steals the show. It decentralises the whole process. new data can only be added or modified if a majority of the network agrees to the change.
No individual or entity can easily corrupt or reverse this process for malicious intent. Not all blockchains are resistant to tamper— private implementations can suffer from centralization which contradicts the whole "decentralisation" legacy of blockchain.
All updates and additions are publicly. This adds to the credibility of blockchain.
Public blockchains allow anyone to participate, and everyone has equal access and rights.
Replicating and sharing data enables redundancy.
For example, in case of Bitcoin, the record can survive even if entire continents go offline.