You don’t understand, you have to submit your tax information exactly because you are in the EU. This is to avoid double taxation. If you don’t submit your info, Envato will automatically take out 30% of US tax from your sales to US buyers.
If you are not a US citizen or resident alien, you will need to submit a Form W-8. If you are a resident of a country that has a tax treaty with the U.S., you will benefit from the reduced or zero withholding rate that is specified in your country’s tax treaty. If you are a resident of a country that does not have a tax treaty with the U.S., then your U.S. source income from Envato will be subject to a 30% withholding tax.
Let me make an example.
If you sell something for $11, Envato will take an handling fee depending on the category (suppose $1), that makes it $10. 37.5% fee (being you an exclusive author). That leaves you with $6.25 if the buyer was anywhere but in the US. If the buyer is a US citizen and you don’t submit W-8, you will lose an addtional 30% of the $10, which will leave you with $3.25. Plus you will have to pay whatever taxes your country asks for, of course.
I did not know this at first and I lost almost $30 because of this.