I'm an American, and I have no idea how someone ends up with that many cards. I carry two: my credit card and by debit (ATM) card. I could easily leave the latter behind, since I very rarely use, but it feels prudent to keep it with me in case I need cash in an emergency. Beyond that, I could understand having a single company credit card if it makes sense for your job (it doesn't for mine).
For gift cards, I suppose it would be nice to have those all aggregated, but I do very little brick and mortar shopping, and virtually no impromptu brick and mortar shopping where having a library of loyalty cards with me at all times would be useful.
The same applies to loyalty cards. I do have a Macy's card, but they can just look that up for you at the store, so I don't carry it. I've probably lost the physical card.
For gift cards, I suppose it would be nice to have those all aggregated, but I do very little brick and mortar shopping, and virtually no impromptu brick and mortar shopping where having a library of loyalty cards with me at all times would be useful.
The same applies to loyalty cards. I do have a Macy's card, but they can just look that up for you at the store, so I don't carry it. I've probably lost the physical card.