@georgetakei I use an app called Keyring to store all of my various cards (Google Wallet works too). Anything with a bar code can be scanned at the store. Worst comes to worst, you can just enter your phone number if you have a registered account.
@georgetakei you eventually even forget which ones you already have, so sign up again. Was just looking at hotels for a trip, and could swear I had the hotel’s program already but didn’t see a login in my password manager.
@georgetakei when they first started appearing widely in the UK, I had a conversation with a checkout operator who asked if I wanted to sign up to be given a discount on my current purchase, paraphrasing , I replied "I come here so often you know me by name, but without the card I'm not considered loyal. The card and reward are nothing to do with loyalty. So, no thanks."
@georgetakei I have no grocery loyalty cards. They are too literally selling your soul for a mess of pottage. One alternative is to get a new one under a fake name and address each time you shop. I've never seen them check the validity of your information.