> How many have a smartphone with a cover able to hold cards?
I use a wallet that holds cards, but not common or popular, and are you seriously suggesting that we insert this thing into our phones, which would probably mean you'd have to dislodge from the case, wallet or not, and align the card into the slot. Not to mention how much space it'd consume in a smart phone. You & maybe a very tiny cohort want this, the general public don't, especially for the marginal security benefit. Anyways as others say, the modern equivalent is NFC, but again getting everyone to buy and carry an accessory is asking too much. Modern smartphones already have modern security and in recent years have been exposing their security coprocessor chip to the OS.
no need to "insert" most smart cards nowadays are NFC and most smartphones have a reader built-in in their battery so all you need is just flipping the "book cover" to allow reading, even without extracting it. On a desktop having a small usb flat reader or one built-in in the keyboard (common two decades ago in various setup, for contact based smart cards back then) or one aside the touchpad area in a laptop could provide the desktop part.
I use it normally to declare my taxes for instance, with a small desktop card reader (ReinerSCT CyberJack) as a "security device" in Firefox to authenticate for instance, just putting the card on the reader, open firefox going to the relevant website, click on eIDAS login, entering the national ID card PIN and being in. A pin for all public sector services, no apps needed, no regular password changes and so on.
I use a wallet that holds cards, but not common or popular, and are you seriously suggesting that we insert this thing into our phones, which would probably mean you'd have to dislodge from the case, wallet or not, and align the card into the slot. Not to mention how much space it'd consume in a smart phone. You & maybe a very tiny cohort want this, the general public don't, especially for the marginal security benefit. Anyways as others say, the modern equivalent is NFC, but again getting everyone to buy and carry an accessory is asking too much. Modern smartphones already have modern security and in recent years have been exposing their security coprocessor chip to the OS.