Instead of being a true rival to FIAT, it became a thing with a toxic-as-hell commumity, fraud, and basically its nothing more than a high risk stock. The risk is NOT only "will this go up or down" but you have a high risk of being robbed, as have happened to millions of people.
Maybe there will be a better alternative in the future, but right now bitcoin is not it.
Using a cryptocurrency (originally) meant basically opting out of the governmental violence-as-a-service for cryptocurrency/-token purposes and taking care of this aspect by yourself.
Depending on your resourcefulness and lifestyle, this may mean
- hiring personal security
- being very careful about privacy aspects, e.g. making it very hard to link your personal identity to your cryptographic keys; distribute your crypto-tokens among many keys so that if one key gets "linked", the attacker will find only few tokens there; use anonymization services; ...
- think about what mitigations you have in place against "rubber hose attacks"
- live a modest life so that people (and also taxation authorities?) don't get suspicious that you are secretly rich, i.e. don't boast about your richness
- ...
Cryptocurrency was a hidden blade. People were drawn in on the promise of avoiding the things they don't like about capitalism, but then cut by a more unregulated version of the same.
If you're going to dismantle all of the institutions of liberal democracy and capitalism so you can send a billion dollars to somebody, why not just go ahead and get rid of money while you're at it?
Quite the opposite: the marketing was always about more "pure", "unrestricted" capitalism without all the "evil" restrictions and red tape that the governments set up and (depending on the cryptocurrency) no option for the governments to turn on the money printing press to devalue the currency by their will.