At first, I'd like to say that SimpleCRUD is a great solution for quick CRUD tasks, especially as an alternative for popular ways of easy sharing of structured data (like Google Spreadsheets).
However, first advantage of DB against spreadsheet is relations between tables. If we have only id-by-id relation, it's easy and everything works like a charm, but how to deal with a one-to-many relations? E.g. if one designs a task list and needs to relate a task to several persons. I can't find a way to do it easily, without implementing all this logics manually.