Perhaps the parent's situation ("software that runs within very secure financial networks" cf https://news.ycombinator.com/item?id=24747781) prevents them to rely on an external service?
We cannot rely on anything outside the client's secure network. There are a few exceptional items that are allowed to talk to the internet, but our system's data persistence layer is not one of them.
Effectively, our client's operations cannot rely on cloud services and all of the related last mile connectivity into their infrastructure. If AWS/Azure/et.al. go down, many of our customers are still able to continue operating without difficulty.
I'd love to understand why you chose that.
Feel free to hit my up at the address in my profile if you don't want to talk here.