Some of the applications crypto folks were going on about: decentralization (of course) until the IRS started taxing your crypto transactions; helping 3rd world countries with weak currencies (partially happened); international trade (quickly became untrue and monitored by government agencies), ledgers for tech companies (they can all already build audit trails. i've yet to see many applications where companies are willing to give up control over their trust to a 3rd party system with no scrubbing functionality. looking at you, AWS status page).
Like I said, same vibe, different applications. Until some are built it's all just hype and conjecture. The applications we've seen work well are already well-accepted for their faults (content generation, summarization, etc)
Cryptobros thought that they are smarter than central banks and didn't bother to implement proper monetary policy in the Bitcoin protocol to prevent its volatility.
Real interest rates are typically positive, so no, you are not.
Want to elaborate? Bitcoins monetary policy is beautiful in its simplicity and predictability. In that sense, it stands in stark contrast to fiat.
No wonder that its adoption for legal purposes didn't go anywhere.