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.
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.
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.
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.