[dazc]

I'm in the UK. If you give me a passport as ID I have no way of knowing if it is genuine. If you present a company letterhead I can, at least, check the company exists, verify your name is the same as a registered director and also see some basic financial history.

[nyokodo]

You can do all of that by just being told the company name, address etc. Why does it have to come in the form of stationery?

[dazc]

It's just another hoop to jump through.