I’m not familiar with it, but it looks like it’s a Proprietary and Freemium product.
If you want a similar product that’s open source and privacy focused, check out memoria. There is a one time payment though.
And there are other open source ones like StoryPad (free, ad-free, privacy focused), Diary Vault (free and ad-free), and Pile (freemium).
I’m not saying this with any snark or sarcasm - But if you really want a journaling / diary experience that has 0% risk of a company mishandling your private data, pick up a pen and paper. Remember to always ask if you really need a digital tool to accomplish your goal, or if an analog version of something with suffice.
Look into Zood (Android only), OwnTracks (iOS and Android), and Grid (iOS and Android)
Also recommend using these resources to find alternative apps, services, and platforms:
Wind gusts are crazy today the way jokes are flying over heads