People with stable living situations can more easily keep track of all their official paperwork and spend the time needed to understand the application process. They also have more access to the internet to do things remotely.

Poor people are more often in less stable living situations and it's easier to lose track of documentation. Not to mention unhoused people who don't have a safe place to keep track of things either and often don't have up to date identification in the first place. Also, with less access to the internet to do things remotely it's more common to need to take time off work to go to a physical branch which may be very far away, requiring taking multiple busses just to prove their identity.

Of course adding more security is important, but it has tradeoffs like this that harm the poor that need to be considered.