So, the difference is it walls off physical card, Apple Pay, and online payments.
But, all online payments use the same number- unlike (one of ) my existing cards which will generate a different number for each online transaction (or so they claim).
it’s no less secure than any of the other cards (for online purchases, anyway).
If I have to hand a card to someone and they can copy the number- Apple Card
protects against copying.
if its used with a card reader, and that has one of those spoofed reader that records the transaction, maybe not a help ( assuming they can create a card with the same number it recorded, unclear if that is easily doable)