I think the new UK system is quite good tbh.
Now with most online transactions you have to enter a pin/password to authorise it, and now they use chip and pin instead of signatures.
Means you can use anyones card without the cashier knowing whether it's yours or not, but if you don't know the pin number, you can't buy anything.
Although once the machine wasn't working, so my friend had to sign instead, and because she never signs, she hadn't signed her card, so she couldn't buy the stuff. She had to go to a cash machine and get money out to pay with instead.
Another flaw is that if you use a tampered cash machine, they get your card details and pin so they can buy stuff in person, but again not always online.
I thought I'd had mine cloned once, there was a dodgy cash machine that I'd used (I didn't find out it was dodgy until afterwards) and I got a HUGE transaction made (£57, big when I only had £30 in lol).
It turned out I'd just gone over my phone bill but I panicked so much at first!