> 1. The card handles also selling some off for taxes every transaction and put that in an interest-accruing account.

> 2. The card tracked my capital gains for each transaction for easy reporting on taxes.

How should it ever do that? It would basically have to limit you to spend Bitcoin that you acquired over that exact same card (like when you buy Bitcoin via PayPal) and that you hold in a virtual wallet provided by that card network operator. Otherwise they'd be unable to tell how many $ you paid to acquire the Bitcoin you just spent.

As a related question: how comfortable would you be with a cryptocurrency-backed electronic payment card that would require you to keep your Bitcoin in the wallet of Visa/MasterCard/whatever (or their associated banks or crypto custodians) in order to spend them?