It wasn't that long ago Google or Apple were Saint. The future is Apple Pay, Cashless, Contactless Credit Card, Crypto.
It wasn't that long ago people that worries about privacy or freedom were over reacting, paranoid, pessimistic.
It wasn't that long ago having physical Cash, topping up your Oyster / Opal / Myki / Suica / Octopus / EZ-Link / Presto or any other Top Up Prepaid Card were dumb. The future is Apple Wallet.
How the tides have turned
IIRC you can’t have a WeChat pay account without a Chinese bank account.
I would much prefer if this was true for most public transit networks in the world, including the rest of the UK.
I'd also argue that in this case the fault is on the cardholder for being with a shit bank when better options exist in the vast majority of countries.
Even if my card worked the first time I wouldn't trust it would work the 3rd or 4th. Until I bought a monthly pass every trip took time and some luck. I wish I knew prepaid cards were an option.
In fact I deliberately own a non-contactless credit card (from my good bank, who were happy to send me the non-contactless version when requested even though their default is contactless) and then enrolled that card in my phone so the phone can make contactless purchases.
Thus, my credit card can't be hijacked to do remote purchases because purchases with the card require a physical connection, and yet I can make fairly large card purchases contactlessly, because my phone vouches for them after I unlock it.
[1] https://www.macobserver.com/tmo/article/when-apple-pay-requi...
EMV lets the card (or in this case maybe a phone) and the terminal (in this case a turnstile inside the station, or a reader on a bus) negotiate what to do, the issuer may not be involved since it's possible they'll agree the entire transaction needn't yet involve the issuer. This is related to one bug in EMV, you could intercede in the middle to tell the card "It's OK, no need for a PIN" and also tell the terminal, "Yes, the PIN supplied was correct" and since the terminal doesn't know the correct PIN you've now got a shim that allows you to use the wrong PIN with a stolen card†.
Anyway, TfL terminals aren't going to agree to signatures. So, if your card really does only work with a signature then you can't use the turnstiles, along with presumably many other modern conveniences.
† There are obvious technical fixes. But the fixes cost money, and fraud is a cost banks can pass to their customers, guess what happens next.
We don’t want to lose this privacy because as mentioned. We’ll never get it back.
Sorry to break it to you but I'm pretty sure that unless you're actively swapping Oyster cards with random strangers, the pattern of metadata of where and when that card enters and exits the Underground or Overground, or when it takes a bus ride (and the route number at least) can soon yield a useful collection of data points (which in turn can be cross-referenced with CCTV timestamps) for any "authority" that's interested in tracking you.
They're human, too. Often dumb, most often uninterested and lazy. And everyone gives up at some point.
In fact most of the decisions around ticketing were more about reducing costs and improving efficiency than reducing privacy (that was just the side effect) for example on buses people paying with cash were massively slowing down the boarding in busy areas, so they made pre-pay or opal only buses during peak hours hours in some areas to improve the on time running. Bus drivers also hated dealing with change and carrying money as well. They were already trying to phase out the use of cash on buses and I think covid accelerated that trend as they now had a great excuse to do so everywhere.
In fact even a few years ago there was already discussion of using CCTV and facial recognition to track people through stations and what they use, the idea being you could then pay for your trip the same way those Amazon supermarkets work as that would reduce the congestion at gates and allow better tracking of full trips as Opal data can't determine your exact route, only the parts where you tapped.
The reality is most people will complain far more about having to pay slightly higher ticket costs than for the loss of privacy, so it's a fairly easy decision for politicians to make and why Australia has so many sweeping surveillance powers.
We only have these cards due to historical quirk (quick contactless technology existed, but not in credit cards), and if we lose them, it’s another thing that we’re never getting back.
(I protested the removal of paper tickets from Sydney’s trains and busses, for what it’s worth…)