Bitcoin is basically a kind of musical chairs for money. People buy in and try to get out and maybe they make money and maybe they lose money. People will play this game, clearly, but that doesn't mean Bitcoin is the future of money anymore than casino chips are the future of money.
Medium of exchange or rather the division of labor. Bitcoin doesn't do it. In fact, most people who like Bitcoin want it to be a terrible medium of exchange. Everytime you hear people talk about Bitcoin on Reddit there are HODL memes, aka people openly proclaim that they don't want to use the money for anything other than speculating that it goes up in value.
They're not speculating that it will go up for no reason. The investment thesis is that it solves real world problems, and that everyone who thinks it doesn't sounds like someone comparing fax machines to the internet in the 90s.
What people are selling as far as DAOs, NFTs, and "smart contracts" where they mean are better and more sophisticated than Bitcoin, can all be favorably described as the application of Bitcoin's critique of money to the issuance and governance of other tokens representing other forms of property, and are inherently more complex. Least favorably described, they are scams to boost leverage powered attacks. The middle of the road might be that they're the naive notion that building more complex constructs on top of what Bitcoin defined is immediately achievable without compromising invariants that matter for useful money.
All to say that the "killer app" critique of Bitcoin probably ins't the best lens, and that if it's more complicated than custody and payments, especially for people where that isn't readily available, it's probably further out than is survivable for a single company requiring the kind of trajectory of those that create "apps".