The whole point of blockchain/cryotpcurrency was for (1) decentralization and (2) transparency, to instill (3) trust and (4) removal of red-tape fees/processes from traditional agencies/banks/domestic-government/medical/data-compliance/national-relationships, etc. At least that's how I see it. The use cases are more niche than people are led to believe in my opinion.
There are some actual use cases for cryptocurrency in Venezuela right now, and countries that have instable currency / government trust. Other examples, Zimbabawe. Decentralization can be a good thing. I see value in that, essentially becoming your own bank. There's security in that model to some extent, and also huge gaping risks as well (e.g. alot of cryptocurrency heists, volatility in a somewhat new market, emerging technology). I'd rather have my money in a bank under FDIC with 250,000 insurance coverage, split into multiple portfolios
Most of the money and volume just comes from overhype and trading. This might be biased, but traders like jumping on bandwagons, its what they enjoy. Trading doesn't really create value, at least for virtual things that most people don't have an entire grasp of. Just explaining how crytocurrency works is already complicated as is, its almost as bad as javascript fatigue.
I won't say that blockchain technology is entirely not useful. I have been told that its been incredibly useful in the medical industry due to (4) red tapes processes HIPPA data compliance, etc. Other examples would include energy markets, digital identity, supply chain mgmt, and asset tokenization. All very traditional red-tape processes involved that can be circumvented. Basically, blockchain/cryptocurrency is essentially an a high level API anyone can access but is only given partial CRUD permissions unless they have a private key to that wallet/secured-data block etc
I still think the cryptocurrencny market is getting oversaturated though. I'm always skeptical of when blockchain/crytocurrency gets thrown around though, its very buzzwordy.
Unless points (1)(2)(3)(4) are met, I can't get behind a project using cryptocurrency/block chain. Always start with the simplest solution first. I'm very skeptical of messaging app succeeeding off using blockchain/cryptocurrency, most people I know accept that privacy infringement is going to happen and backing up your files/systems locally is always a thing.