There is another reason as well - at least in the UK if you are VAT registered. You need to know if your customer is in the UK, EU or outside of the EU, and if

There is another reason as well - at least in the UK if you are VAT registered. You need to know if your customer is in the UK, EU or outside of the EU, and if they are a business or not (their own VAT registration number), so you know if you need to charge them VAT or not. When the tax man comes calling, you need accountability to ensure that you have been charging the correct amount to the correct people. Extremely frustrating for purchasers and sellers to need to provide and collect all of that information simply to accept a payment. Far too much friction.