The original cryptocurrency that launched the whole scene into relevance.
It is hard to dismiss Bitcoin as it is such a foundational pillar of the whole cryptocurrency sphere. If it is a good day for Bitcoin, it is a good day for everyone else.
* Proof of work.
* Widely used, and its proof of work trust mechanism is inefficient, making it environmentally disastrous.
* Inefficient in what way? It clearly is working as it was designed.
Its creator is unknown, and this video reveals a lot of the lack of community driven nature of the project. This may be a project that people will have to ultimately put up with, maybe laws down the line force bitcoin mining to use renewable energy at wide-scale. But, it is fraught with problems that are difficult to change unless a near unanimous decision is made by all of the miners. And there are more conflicts involving the development with Blockstream and communication channels preferred for the developers / miners.
Bitcoin - Unmasking Satoshi Nakamoto (May 11, 2020)
There are only, on record, about 17 developers on the core of bitcoin. That is a substantially tiny number in comparison to the user-base which take advantage of the software. And these developers are mostly afloat by grants provided by other companies. It can be understandable in order to keep development focused, however due to the nature of the software project, wouldn't it make more sense for the software to have a more open ecosystem? Like that which happens with the Linux kernel?
Bitcoin’s Future Depends on a Handful of Mysterious Coders (Feb. 16, 2023)
List of people who have had commit access to Bitcoin Core (February 01, 2017) Constantly updated
Whitepaper: https://bitcoin.org/bitcoin.pdf