No, you are confusing "wallet" with "address". A wallet is little more than a seed for an RNG and a log of transactions. Every new transaction starts with a source address and results in two destination addresses: the primary destination (payee) address and the address where the remainder of the source balance goes. You definitely want to maintain control of your change, so your wallet uses the seed to deterministically generate a keypair for a new address and that is where your change gets sent.

I've got no interest in digging into their methodology, but feel pretty comfortable assuming that they've grossly misrepresented all of the above as "accounts".

i dont mean to be condescending, but how could they implement privacy without centralizing? like the bitcoin card provide must hold all your assets for you for you to gain privacy, no?

I believe they were talking about Bitcoin wallets, not card providers.

Is it worth for privacy even though transfer is trackable?