Re: Unmentioned option
"Is this because its more effective than solutions involving mobile phones? Or is its security so bad that no-one dare mention it."
Yes.
The problem is if you lose the card who will issue a new one the same day, setup and ready to use with all the existing accounts?
Even my bank can take a week to post out a new card, so while secure it breaks an essential online service if you ever lose your card, which for bank cards is the time you need that service most, which is why banks have mostly now moved to other methods such as dedicated apps. For all other services they would all either need their own individual cards, or need to share one card, both of which can then become another security nightmare to manage both for users and the services.