What should a money app for Singapore never do?

We are building Sum, a money app for Singapore that brings your bank accounts, cards, CPF and HDB flat into one place. It launches here on Product Hunt soon.

Before launch, I'd like to hear from anyone who has tried a budgeting or net worth app and given up on it. What made you stop? And what's the one thing a money app should never do?

A few things we've already ruled out: Sum is read-only, so it can't move your money; it never asks for your bank passwords; and it doesn't sell your data.

Sum is only for Singapore for now, but I'd like to hear from anyone, wherever you are. I'll read every reply.