Germany does taxes automatically in many cases. If you are just a regular employee you don't have to do anything. You usually only fill out a tax form if you have some extra expenses to declare for which you would like to get some money back.
They even know that I bought apartment(shares for it). And I didn't report that to anyone.
I only went online added some deductions for using my home for remote work, half of the internet and some equipment I paid with my own money. About 5-10 minutes of work for some tax-money back.
I really see no reason why make life complicated for your average worker.