Being a bank, we need to know who each of our clients is.
The Bank of Portugal obliges as much, as part of anti-corruption and anti-fraud measures.
Since you don’t need to go to an agency, and you can do everything over your smartphone using Chave Móvel Digital.
To do your identification through Chave Móvel Digital, activate that option through https://www.autenticacao.gov.pt/a-chave-movel-digital and then follow the steps in the app.