In a more general sense...
(1) a bitcoin cannot be counterfeited
(2) the mathematics is such that there can only ever be 21 million found/mined/in existence
(3) a lot of the bitcoins that already exist are lost, and can never be found - once the key is lost the coin is lost forever - anyway the supply is limited
(4) hockey cards and old coins, old stamps - they have value because they are scarce, limited in supply, and there are willing buyers and sellers, so they have value. Same with bitcoin - who cares if it's an asset, a currency, or what
(5) People with serious money think that bitcoin has value, as do a lot of people without serious money
(6) There are a lot of handy things about bitcoin, currency-like uses, store-of-value like uses, legal and illegal uses...etc.
(7) the value has been all over the map, don't know if there has ever been any other asset that has been up and down so much, and in the end, to date, is so valuable. Considering that when it got started it was worth a fraction of a penny. And recently has been over $60,000. No stock has ever done that.
So, volatile, yes. But with enduring value? I think so. I don't own any, but certainly regret that. When I first looked at buying bitcoin they were in the hundreds of dollars. So yep, wish I had. At current prices...probably not. Just admit the ship has sailed and live my life without.
Like anything on the planet, the value is whatever is someone is willing to pay for it, but at some point people are going wonder why the fuck they are paying so much for it, or paying for it all for that matter. Bitcoin doesn't produce anything. You can stare at it all day long and no magic rabbits are coming out of hat. So someone else might buy your bitcoin for more then what you payed for it, but now they have the problem of trying to sell it for a profit. It's not fiat money, so people can get kiddy as much as they want about different platforms talking accepting it, but will never be widely accepted like fiat money, and anyone who thinks otherwise is fooling themselves.