Budse is a loosely-coupled budgeting application. And by loosely-coupled I mean it doesn't actually control your money or actually know about it. It's a tool for you to check whether your budget is working.
Some hackers are good. Some hackers are great. Therefore there is no connection to actual bank accounts (and consequently no access to your actual accounts).
As a budgeting application it generally follows the principles of bucket (or envelope) budgeting by allocating amounts of money to different sub-accounts. These sub-accounts maintain a running balance that track how your budgeting is going. Approach zero and you're right on target. Have a surplus, and either you're over-budgeting or purposefully setting yourself up for a splurge. Have a deficit, and you're going to need to take another look at your budget.