Yes, real mainstream use cases are a good measure of tech success. At least, I'd want to see some plausible early mainstream use and a path for it to broaden.
It's very typical that spruikers of tech hype cycles focus on the amount of press coverage, the number of projects rushing into the space, the amount of developer interest, or highly extrapolated market numbers. It doesn't prove anything about whether the thing has any real value or will be around in 10 years.
Given the allegedgedly vast scale of cryptocurrency deployments, there ought to now be some real uses and I don't see any, other than black markets, money laundering, speculation, and ransomware. Those are always going to exist and may be a stable base but probably aren't enough to justify the hype.