Why did the price of bitcoin increase so dramatically? I read this question on money.stackexchange, in which a user asks how to tax the speculation gain they (involuntarily) made. This guy (or girl) bought BTC for a few hundred USD a few years ago, lost the respective harddrive, and when they found it again, the BTC were (supposedly) worth a million or so USD.

So I am wondering, why did BTC appreciate so dramatically in other currencies? Is it just because of rising demand, in turn due to increasing trust in BTC?

As a corollary, could the BTC appreciation also be driven by a speculative bubble?



Sorry if this is a very noob question.
some reasons for the price-increase:

-bitcoin becomes an official currency in japan

-Australia Will Recognize Bitcoin as Money and Protect Bitcoin Businesses, No Taxes

-many people know/buy bitcon now, who did not know bitcoin some months ago (in many countries) caused by increasing media coverage

-bitcoin becomes an alternative currency in venezuela, Nigeria and some other countries caused by internal political problems

-the scaling problem seems not to be finally solved but the segwit-activation could improve the scaling-situation

-Russia’s Parliament is Discussing the Legalization of Bitcoin

-meanwhile the blockchain-technology is more established: there are no known hacks of the blockchain self