@authorjona Okay I got it now. I have some concerns also, I don't know if I sign a contract with the app there won't be any concerns anymore. Check it out:
On Amazon KDP, I earn up to 70% royalties for every book sold. My books appear on Amazon marketplaces worldwide (US, UK, Canada, etc.), but that’s not the case here. I keep 100% of my right with Amazon kdp, I decide the pricing, format, and even when I want my book to be updated worldwide. KDP allow me to be both read digitally and physically in people's hand, but here, only digitally.
Once on Amazon, my book can stay available for years without losing visibility. But here, I discovered stories can get buried in search results after a while. There are much other differences which I hope I will meet here which I didn't.