We think of it more as a database++ with financial primitives baked in, so we want to keep it very simple and dumb. It’s not a complete solution - it’s a book to write in, and you need another service that decides what and how to write and writes it (we call it the bank or teller service, and it’s all business logic for our business). Each product has its own bank to teller service, but they all use the same ledger underneath.