[GLjEI4YbnGD27LB]

The blockchain is really inefficient for making others store your items. It is there to make sure others can only modify your stuff in the way that you specify, and others can trust they have a genuine copy of your data.

[edanm]

You don't need a blockchain for that, you can just hash/sign your data (or changesets).

Blockchain's innovation is to allow a group to come to a consensus about a change that happened, that doesn't allow one person to later say "no no I meant something else". I.e. no double spending.