Theoretically cryptocurrencies are interesting, but Bitcoin just isn’t usable.

Bitcoin and many other currencies have way too many and large fluctuations in value for daily use.
Bitcoin specifically is not practical for transactions in general due to cost and block size limits. Yes, lightning exists, but maybe your technology is shit if it needs a second overlay network to function.
Instead of fixing those issues, most other coins are just pump and dump schemes for a quick buck.
Only very few coins try to do something different and fix some of these issues.