GOV.UK seems conflicted about it lol "You usually do not need a BRP to open a bank account. Contact the bank to check if you’ll need a BRP or if you can use a different document." https://www.gov.uk/biometric-residence-permits/prove-your-st...

"The biometric residence permit is proof of the holder’s right to stay, work or study in the UK. It can also be used as a form of identification (for example, if they wish to open a bank account in the UK). https://assets.publishing.service.gov.uk/government/uploads/...

:')