You can use the CSMB account as any other account but it is only valid for people living in the country. It was created for who need or wants minimal bank involvement. The card is only useable in Portugal and has no Visa or Mastercard connection; it can not be used for internacional purchases, although that will probably be solved through the eEuro.
This is the page for our regulator on the said account. There is a PDF available for download I assume you can translate through Deepl or a similar website.
The last time I read on it, all banks were required to offer such account. The banks you mention - neo-banks and fortune managers - are not usually on the bracket of clients you are considering.