It's really not a grow only, there you have immutable data but it expires at some points regarding the rules you want to implement.

The integrity of the data is not shared on the network, each user owns his data, and choose to store it on his desired server. It's really like the email system.

For the article, it really joins the conclusion that you could build google doc, or an IOT system or anything but you will inherent from powerful synchronization, encryption, offline mode and so you can ensure the 7 principles the author of the article characterized.

You could just use a cloud to store massively your data, and pass them through a local server to make sure they are not compromised.