I remember hearing something about a bitcoin credit card. Like, one that you pay for everything with fiat on credit, and then you pay off your bill in bitcoin. So you never have to hold fiat if you don't want to.
What's the best/most reliable credit card that does this?
I haven't seen a card like this, and I don't think many payment remitters would be willing to offer a product like this. It's too easy to simply get a credit line on a regular credit card, which will most likely have a higher limit, and pay the bill after the fact in bitcoin. You could even use a bitcoin debit card to pay the bitcoin credit bill, if you didn't have a way to convert the btc.to fiat.
A credit card that you can pay off in btc doesn't really have any advantages over a regular credit card, they would be the same instrument.