For example we wanted to get internet in the apartment we were renting. The local ISP (Orange) said that we needed a Spanish bank account, we said that we had a European account so could make an IBAN transfer, but apparently that wasn't an option. So we went to the bank and they said my wife needed a letter from the police. So we went there, and after showing all her university documents and waiting there for half a day, she got that. By that time the bank was closed, so we went back the next day, and after another few hours she had a bank account. We made a transfer of a few hundred euros from our other European account at home, then once it arrived a few days later, went back to the ISP. They took our details and the first payment, and then we figured everything was fine.
A month later the first bill came and we tried to pay but it was declined, tried to log into online banking and that was blocked too. We went back to the bank (BBVA) and they said our account had been closed due to suspicious activity (the only transaction we made was the initial payment for the internet) and there was nothing they could do. So we went to visit the ISP with the intention of paying in store, but they said it wasn't an option. We explained the situation and said there was nothing they could do, we could only pay with a Spanish bank account. In the end we had to get a friend to make the ISP payment for us, every month while we were living there.
Compare this to where we live now. You simply make payments to an IBAN bank account, so it can come from anywhere in Europe. If you need a local bank account, you can easily do so in any bank (I opened an account before I was officially living there, i.e. without any local ID, just my passport) or use something like Revolut. If you need to get a local phone number, you just go to the supermarket and buy a prepaid SIM for €1 - no ID needed.
