That's not legally sound. They can claim to have still been providing the services you contracted for (whether you used them or not) and get a court judgement against you.

How so? The cancellation request has already been made in writing. This just adds protection against the merchant continuing to charge you.

If the merchant attempts to continue to charge you, it's because they have some argument that they're authorised to (e.g. they didn't receive your cancellation request). Getting a credit card charge you can dispute gives you more visibility and makes it easier to show good faith.

I could see this having problems for credit dispute.

For example, your Chase card pays Piracy.com. Some vendor makes an unauthorized charge on your Privacy card. Now you have to deal with Privacy's policy instead of your bank's policies to dispute

Yes, disputes have to be done through Privacy from what I understand. See: https://support.privacy.com/hc/en-us/articles/360012288114-H...