Are All These Membership Cards Really Needed ?
 

I've got an AirBaltic "BalticMiles" membership card, as well as an ANA mileage club card, and an Hilton HHonors Silver card. I'm registered to many more clubs, but these are the only cards that I've been given. Anyway, are they really needed? I'm departing for a 1-2years of traveling (ultra-light), and trying to get rid of any items that I do not really need. Are these one of them?

Yes and no.
If you are only collecting for rewards moat airline/hotel only need the number. Some reatil loyalty programs requires the card to be scanned.
If you did not get a card but an account number then one can assume that the number only will be ok.
However for airline /hotel lounges access having a card is a good idea.

I've got an iPhone/iPod app called KeyRing that has all my (and my husband's) FF and other loyalty program numbers. The only actual cards I make sure to carry in our travels are PrioirityPass and my BA Elite card, both of which are needed for lounge access. This has greatly reduced the amount of plastic I carry around.

Hmmm I'm also a member of PriorityClub and AA, Delta, British, etc.. and didn't get a card as well, but I see many people DID get a card here in these forums. How come?

Lounge access? Can I really expect this from the regular Al Nippon Card or the Hilton silver card?

Some partner airport lounges may deny you entry/access if you don't have your own airline's frequent flier card (i.e good luck getting into a LH lounge without your UA Milage Plus Card showing your status ;))

That's why I carry my BA card. It's the only one with Elite status on it. For the rest, knowing the number so I can make sure it's on the flight record or hotel reservation is enough.

Not so much these days as airlines print one's status on the boarding pass. However, I have needed the hotel card a couple times to get an upgrade when my status has shown incorrectly. I really don't need my supermarket card as it's easier to enter my linked phone number on the keypad instead.

As an aside, a companion and I went up to the Delta elite clerk for intl check @ JFK years ago (we had just made Silver - woo hoo -- cards hadn't arrived yet) -- before looking up our info, the agent warned us: "If I find you don't have any status, you're going back to the end of (cattle) line without boarding passes."