While not wrong I'm not sure the publisher is uninterested as they are a competitor.

E.g. this is how they criticise obsidian - suggesting that a default location backup is somehow worse than default cloud sync is just very strange to me.

Obsidian stores your data as a folder of plaintext files on your local computer. You are thus responsible for securing this folder and making it available on your other devices. This is particularly difficult on mobile platforms that lack access to a robust file system.