Maybe it's just me, but we all place an awful lot of trust giving vendors essentially all credit card details possible AND where we live so that they're capable of skimming a self defined sum off by themselves. It's like an inherently insane system. We're supposed to be the one wiring the cash, not the vendor themselves with our data.
Because your contract here is with the subscription service, not the bank.
Just as you can’t cancel your brothers subscriptions, the subscription service has no reason to accept a cancellation request from your bank.
Even if the service was no longer able to charge your card, you would still owe the money. The debt you incurred monthly is separate from your choice of how to pay that debt.
By that notion, the fact that almost all home locks are easily pickable and glass windows breakable is also insane. There's tons of valuables behind almost all of these!
We found meaningful ways of disincentivizing theft, which turns out to be largely sufficient even in face of fallible security. The exact same applies to card data in the hands of merchants.
Take that logic and apply it to crypto and hopefully that'll help you understand why crypto enthusiasts believe in it.
The fact is that we can and do find ways around flaws in a system. Crypto folks just think that a crypto foundation is better than the current foundation of our financial systems.
Credit card issuers and processors only grant merchant accounts to vendors who have shown themselves trustworthy. While the system isn't perfect it works pretty well. If a vendor has many charge backs then they will be subject to higher fees and then account termination.