Bitcoin holds value because of the people who uses it. This crypto currency has a unique decentralized feature thats why it attracts investors or even ordinary people to use it.
Yes it has no proper price because the market dictates in other words those people who uses it dictates what would be it's price value.
Bitcoin is one of good example of a volatile currency because no individual has the power to control it but the majority itself decides if this digital curency is over or will continue to pump.
Throughout the years bitcoin has survived countless bubble but look at bitcoin now.
Looking at it, it should just go back to its history price. The rarity of it should give it more value as if it is like gold that will be depleted in the long run.
It is lined up with commodities and currencies so there would really be no proper price. It is leaning to the usage of people who have it and to how much demands will come. If nothing will be left to earn or to buy or even be mined then it will become more expensive.