Does the "rewards card" actually pay out in Bitcoin? I get something like 3% back on my credit card... which ultimately winds up as more Bitcoin I can use/save in.

Like I posted above, I use Bitcoin where I can there just aren't many places in the United States. Western Europe much better, but it's a bit out of the way at the moment.

I believe in 30 years we'll have ~1 billion daily Bitcoin users across the full spectrum of custody... all the way to from full self-custody of UTXOs and channels to custodial wallets to ETFs to derivatives to even banks. "1991 + 30 years = 2021" of the internet that's the model I compare it to.