Signature deals, don't have to wait as long between posts/PMs having an avatar, getting to own something that is scarce/rare.
There is no waiting time for anything but a brand new account, and that time is, as I remember, 3 minutes.
Sig campaigns? As I understand it, the account in question was bought for .75 BTC. Just how much do these sig campaigns pay?
But sure, passports also have uses beyond identifying the holder--I bought a passport to prop up a table with a short leg.
I bought a Sig Sauer to use as a hammer, trying to fix that rickety table, but I guess I'm not much of a carpenter, so passport fix it is

How's that?