I don't want a public ledger with all my payments, which tells not only what I consume, but also how much I am able/willing to spend.

And as soon as you are in massmarket you need ways for humans to intervene, for handling complaints, mistakes, whatever or dealing with the unavoidable case that individuals lose their secret keys. Or even cases like medical restriction or inheritance requiring others to take over the funds.

All those things Blockchain purposely and inherently prevents.