Being German it feels weird reading someone praise our tax system. The problem here is that you almost always pay too much tax and will be reimbursed when filing a return while at the same time the German Finanzamt already has the required information to do that on its own. But it won't. End of story is that tax returns are exclusive to people educated enough to take of it. And even if you take care of it in an informed way doesn't mean you will be reimbursed fully. For that you'd need to hire a tax attorney in many non-trivial cases.