We have something similar on the roadmap as well. The wavecard already allows you to spend Bitcoin anywhere globally, by selling it at the last possible second and funding the fist payment for a merchant. You can either connect your LN wallet to spend from self-custody (via NWC) or store BTC on the wavecard custodially. Technically, the custodial BTC balance could be collateralized for a loan that is also then folded back into the same BTC on the card, essentially working like a “boosted” Bitcoin position that is partly spendable without capital gains. We’re on the same mission to not hold any fiat whatsoever, and to automate all liquidations into fiat at the recipient level, so that you, as a Bitcoiner, wouldn’t ever need to even care about any fiat balances.