Bitcoin was originally created to be anonymous, decentralized, and mineable on CPUs. In the present time, bitcoin isn’t really any of these things. In terms of privacy, at its best bitcoin is pseudo anonymous. Anyone can see your transaction history and the amount of money in your bitcoin wallet. All it takes is them knowing what your wallet address is. For instance, if you were to receive a payment from someone or if you were to send money to someone, they would have access to your wallet address. From there they could see your spending habits and see the bags of bitcoin you’re holding. Combine this with the advanced block chain analysis tools that now exist, and the fact that most Bitcoin is bought on exchanges where KYC laws are enforced, this makes Bitcoin an extremely transparent currency, even more so than FIAT.
Bitcoin was originally designed to be mined on CPUs. If you don’t know what mining is, essentially you’re putting your hardware to work to solve cryptographic equations in order to verify transactions on the block chain. This is what makes cryptocurrency decentralized. Instead of a centralized authority (such as a bank), you instead have individuals all around the world verifying transactions. The creator of bitcoin originally intended for bitcoin to be mined on CPUs since everyone using a computer has one and therefore your one CPU = 1 vote on the blockchain. However, people started mining on GPUs which proved to be way more effective than CPU mining. Eventually, special computers called ASICS were designed solely to do one task (mining bitcoin). Now these ASICS dominate the network. Unlike CPUs, ASIC miners are hard to obtain since they’re primarily used by the companies that make them. After the profitability of mining goes down, these ASIC miners are then sold for extremely high prices. ASICs are usually not profitable for the consumer and are mainly used by large mining operations. Fast forward to now and 75% (some people speculate that it may be higher than 80%) of bitcoin mining is done in China by companies or people with large amounts of money and ASIC miners. This is why Bitcoin is no longer decentralized, since everything is centralized in China. Instead of 1 CPU = 1 vote, thousands of ASICs = 1 vote.