Budget software usually starts at the dashboard — the chart of what was spent, drawn after the fact. That chart is easy. What is hard is the moment before: someone wants to spend, and something has to decide whether they may, using a number that is actually correct at that instant.
The limit check that counts other people's pending requests. The approval chain that knows who is on leave. The record nobody can quietly delete. The chart came last, and it is honest because of what is underneath it.
Entries cannot be deleted or duplicated. It makes corrections slightly more work and makes the record worth something.
Hiding a button is not a permission. Every right that matters is checked where it cannot be bypassed.
Real organisations have parents and subsidiaries, and pretending otherwise turns consolidated oversight into a workaround.
Declare one budget, raise one request, and watch the figures move.