Why is traditional mailing still so relevant in the US (especially banks) when the technology is so much more advanced?

I know the US is a shitshow right now but please im looking for sensible answers.

I have some documents from a bank that need to be mailed. PDF is not an option and no matter how much i push for a secure email option, they still stick with slow turtle mail.

I live outside the US and this slow mail process has been very frustrating. And not just banks, any other business if you request some form of paperwork, their answer => MAIL.

That is very weird consider to mail the document, they need to type out an electronic version then print and mail it. So why waste too many steps?

And i just discovered today theres a thing called mailforwarding service… Aka you buy a US mailbox, letter gets sent to that mailbox then they help to forward those internationally.

In contrast to when I am in China and Singapore, EVERYTHING is digital. It is so much better that the only thing i carry is my phone.