Maybe it is magical in the American sense, but i can't say i get the big whoop from the European side of the Atlantic...
Admittedly being out of battery is a hard problem, but I chose my phone partly because it has decent battery life.
Two, if "faffing about" is your concern (thank you for that expression by the way, i'm going to start using it), pulling out a card is not really much different from pulling out a phone. But the Apple Watch supports Apple Pay, and that way you don't have to pull out anything. It's really convenient.
If you're wondering how it works securely with the watch, it's pretty smart. You unlock the watch with a PIN when you put it on. It senses when you've removed it from your wrist, so it just stays unlocked until that point. Therefore all Apple Pay purchases are PIN authorized without having to prompt you for it or a fingerprint. All you have to do is wave your wrist by the terminal and confirm.