[TheCapeGreek]

Passports have verifiable codes on them. Letterheads can be copied like word docs.

Granted that's not to say people will actually verify passports using the data, but it is there compared to a letterhead being effectively just a random doc template.

[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.