As an independent Author without any history of publishing, and without a celebrity bonus it is hard to get noticed by Publishing Houses. They just don’t even bother to send an email to reject a proposal, half complete book. So the other two options would be to not publish at all or self-publish.
Being based in Germany and writing an English Book, it didn’t make sense using a German Self-Publishing Company, so Amazon was the only real option.
I also keep total control of the copyright with Amazon, which you would normally give up when going through a traditional Publisher.
As the book is only printed, once an Order comes through, there are no mountains of ready printed books, so I can put some changes through, all within the constraints of maximum 550 pages…