The issue cryptocurrency has is that it doesn't really solve any problem that traditional currency hasn't already solved... other than problems we don't actually want to have solved (e.g., it does make it easier to dodge taxes, to fund crime, and to bankroll terrorists).
There are at least two huge problems with bitcoin from the point of view of someone looking for a currency, as opposed to a way to hide money from authorities, or just a pyramid scheme gamble:
(1) It's hard to spend. Few places accept payment in cryptocurrency, so you end up having to convert to a real currency, first, before you spend.
(2) It's obscenely volatile. Like as recently as November, Bitcoin closed at 67,566.83. Now it's 28,294.29. Generally, you don't want a currency that loses over half its value that quickly. Even taking a twelve-month stretch, it's like suffering from around 50% inflation, in terms of what the buying power of one Bitcoin is today, versus what it was a year ago, in real goods and services.