The ideology behind BitcoinThe root problem with conventional currency is all the trust that's required to make it work. The central bank must be trusted not to debase the currency, but the history of fiat currencies is full of breaches of that trust. Banks must be trusted to hold our money and transfer it electronically, but they lend it out in waves of credit bubbles with barely a fraction in reserve. We have to trust them with our privacy, trust them not to let identity thieves drain our accounts. Their massive overhead costs make micropayments impossible.
With e-currency based on cryptographic proof, without the need to trust a third party middleman, money can be secure and transactions effortless. - Satoshi Nakamoto
The Times 03/Jan/2009 Chancellor on brink of second bailout for banks - Genesis Block
So the fundamental ideology is a decentralized trustless system to create an economy not dependant on governments/banks, empower repressed economies, disrupt or weaken the centralized monetary system, and economic freedom.
Something like what John Holloway said, "Changing the world without taking power."
I think majority of the early adopters were motivated by this philosophy, price wasn't a criteria.
The technology behind BitcoinThere is no denying the fact that Bitcoin/Blockchain technology is revolutionary. It is here to stay. We will be seeing more use cases of it in future. The first distributed blockchain was conceptualised by Satoshi Nakamoto and was implemented as a core component in Bitcoin and thus making Bitcoin a technological tour de force.
Technology is one of the major reasons for Bitcoin adoption.
MonetaryThe monetary aspect is profit. Adopt Bitcoin for making money. I do believe that a good number of recent investors/speculators are in for money only. Leave aside ideology, even a few doesn't bother about the technological aspect. Nothing wrong in it. It is like a get-rich-quick-scheme.
So why did you adopt Bitcoin? There might be a reason or a couple of reasons or all the three.
Edit: Added all of the above.
Bitcoin have its own ideology of being a decentalized system that not like in the bank regulation,they run the monetary sytem thats not depend from centralization and the technology of cryptocurrency is different from the fiat currency system that run only in the banks that regulated by the government,unlike bitcoin even its not regulated its run through the whole system of digital currency.this the unique of bitcoin different from other,thats why people embrace and adopt its three fundamental.