Even if used in the physical world, Bitcoin is necessarily traded online, so it’s still the currency of the internet, even if it's not that widespread yet, he have VPS sold on SAT, crypto card to pay in fiat from BTC etc it's not that bad all given. Nostr has the potential to really spread it IF it becomes visible to a large enough portion of the population, and to do that, it has to offer apps (clients) with features that attract the masses. For now, the skeleton is there, but the shells built on top of it are still too crude for the general public. In my opinion, it's no coincidence that we're seeing the strongest wave of censorship on various commercial platforms alongside expensive hardware, age verification, and so on from a regulatory standpoint. It's a way to take IT away from the masses just as they were starting to get fed up with the commercial model and look for alternatives, alternatives that were starting to be within reach of users who aren't exactly tech-savvy. That’s the hurdle. It’s not about being the currency of the internet; it’s about reaching a model of widespread desktop and home servers computing for many, as opposed to the commercial model pushing mobile for all. It's about having a personal mini-server instead of an ISP router, an Umbrel/Start9 style setup distro + iron, preinstalled, complete with its own Lightning node, bundled with a few hardware wallets to use via NFC at POS terminals to pay for even a coffee in SATs. Then it will be a widespread currency, because the average person doesn't care about the tech nor understand digital ownership, but they do understand, at least a little, when they're in a cage, and if they find an easy way out, they'll take it. As of today, that easy way out doesn't exist for most people, but we're relatively close.