EU accounts have always been audited, Commission independence is a safeguard
The accounts of the EU, and its predecessors, have always been audited. By the independent European Court of Auditors. The oldest report available online is for 1977. In 1977, errors were found. And put right.
The accounts of the EU have been 'signed off' every year since 2007. The Court audits the European Commission's accounting service, and all other recipients of EU funding.
Why does only the European Commission have the "power of initiation"? To formally start the process of making or changing EU law? Because it is a safeguard. To make sure that what is proposed is within the terms and spirit of the treaties. And generally in the interests of all the member countries as a whole.
There is plenty of discussion first. After a proposal, it can be changed by government ministers. The Council of the EU. And in most cases, changed by the directly elected European Parliament. For most things, both houses have to agree.
For most things, at least 16 out of 28 countries need to be in favour. Representing 65% of the total population. Sometimes a higher threshold is needed, or unanimous. In most cases a majority of the European Parliament is needed as well.
Please see "How the European Union works" by EU Publications Office.