Bitcoin in theory should not have any value because it's not backed nor does it have "physical inherent value."
This means that unlike a gold coin which if the government stops backing it, it would still be worth its weight in gold, bitcoin would be worth nothing. (To be fair, nobody issues rare metal coins any more).
However, the government backs its money and guarantees that it would be accepted within the country.
Nothing like that exists for bitcoin, nobody
has to accept it.
At the beginning most of the people accepting it were people who wanted untraceable money and this is still something being done regularly. A way to hide money in an online wallet and transfer it without anybody being able to trace it. And this is still one of the main uses for it.
On the other hand, bitcoin holds a useful framework for transferring money in that you don't need to go through intermediaries such as bank transfers, money transfers, etc. However, no matter which way you go there are still fees anyway.

There's the price of bitcoin with respect to the USD over the last year.
And if you look at it like that it looks very much so like a stock.
Another issue with BTC is that it heavily favors the early adopters of bitcoin, similarly to stocks. Because instead of releasing more BTC in the market, diluting it and bringing it back to a rough baseline value, BTC works on being highly divisible. Meaning that instead of 1BTC being worth $20 like in the past, it is now worth $400. Meaning that .05 BTC is now $20.
But what of those that bought bitcoin when it was $20? Well they now have $400 worth of Bitcoin. Does this remind you of something? Like maybe buying google stock for $200 and now it's worth almost $800?
Another issue is that bitcoin is not the only crypto currency and without easy and fast exchange between them we'll just face an issue where we have dozens of crypto wallets. To be fair, the others are not as popular as bitcoin.