A blockchain allows us to build decentralised systems in which we can trust, thanks to base consensus, that:

There will be enough incentives for network participants to act honestly.
System data will be stored in several repositories (amount equal to how many nodes the network has)

This data will always be available and easily verifiable by any user.
The information cannot be deleted or modified once it has been saved.
Collaboration between agents who do not know each other but share a common goal will be made easier.