How secure is this? For example in the Netherlands creditcards are showing a secret number on the backside of the card. Let's say the app on the phone is altere

How secure is this? For example in the Netherlands creditcards are showing a secret number on the backside of the card. Let's say the app on the phone is altered and making pictures of the card once it swiped over. The phone can then collect all information to make a purchase. I would not trust somebodies phone to swipe my card over.