I carry my SQ PPS card everrywhere, everything else is in my travel wallet which I don't always bring. For hotels, it's easy to just tell them my acct number. The PPS card I carry because it'll ensure that I get my perks when I travel Y class - i.e. lounge access and preferential seat assignment, as well as the right to check in on the business/first class lines where applicable.
As I am often in smaller airports, it's easier to flash my card instead of trying to explain why I am in the business class check-in line on an economy ticket. I'm also assured my status is recognised in case the system is down or slow.
Also, for PPS, it gives me access to their downtown service centre, which is card controlled.
[This message has been edited by fimo (edited 04-26-2002).]