It happens in quite a few countries, even in the USA. It depends on the card processing bank that the merchant is using. Some request that the merchant document validity of the card in "card not present" transactions.
You find it most when a charge is done manually, such as sending your card details to a Travel Company or hotel and then they process the charge manually, usually at a later date. It provides some assurance that when they try to run the card, it is actually yours and not something that will show up stolen after they have already made bookings and arrangements on your behalf.
If you are paying immediately through an online system, they usually don't need this, as you provide some form of verification such as the CVV and billing address right then and there. And the charge is authorized before proceeding with finalization of your booking.