And because the tax years don't line up, it's more costly than filing just in the US, or just in the EU, plus if you moved with a company and were granted RSU's in the US, or keep property or assets in the US ... it's just a pain to calculate properly.
Have friends who regularly spend 10x more than I do my accountant for my tax return because of this.
It would be a bureaucratic pain but if I were to move back to Europe (having become a US citizen) I don’t expect I would end up paying any tax to the US after applying the foreign tax credit.
But there could be a whole lot of complexity around stuff like ETFs and mutual funds and whether they were recognized by both countries.
