[jl6]

> As to your second point, security through obscurity is generally believed to not be worthwhile.

Security only through obscurity - sure.

But obscurity as an additional layer, as part of a defence in depth strategy, still has some value.

It’s rare for any large org to publicly discuss any details of its security design, let alone a bank. Monzo must be supremely confident in their system to go public with this information, or judge that the marketing/recruitment benefit outweighs any potential risk.