Why I Hate Bitcoin

by Axel Boldt

1. Wasteful

Uses about 0.5% of the entire world's electricity production, which is roughly the power of 15 constantly running nuclear reactors. [source]

Few legitimate merchants accept bitcoin.
Not scalable: network maxes out at about 5 transactions per second.
Transactions take a long time to be recorded in the blockchain; afterwards they cannot be retracted.
There are many faster and cheaper ways to transfer electronic funds internationally.
A poor store of value: price is highly volatile and it is unknown whether Bitcoin will remain usable in times of crisis.
Main use today: speculation. Minor use: crime.

Bitcoin exchanges keep the private keys of their customers' bitcoin holdings. Several large bitcoin exchanges lost customers' deposits after having been hacked. [source]
Wallets kept on personal computers are difficult to secure. Because of zero-day exploits, wallets should be kept on "air-gapped" (offline) computers. You have to consider the risks of hardware failure, hacking, extortion [source], death.
You need to trust escrow services and/or companies that claim to store bitcoin securely.

Bitcoin is the currency of choice on the dark web, to buy drugs, counterfeit money, forged identification papers, child porn, stolen credit card numbers, zero-day exploits etc.
Bitcoin and similar cryptocurrencies are used in extortion schemes called "ransomware", where the computer systems of companies, hospitals, city governments and private individuals are disabled by hackers.
Scam victims are directed to use Bitcoin ATMs (which allow to buy bitcoin with cash) to transfer money to the scammers.
Numerous illegal "mixing services" and "coinjoin privacy wallets" exist to aid in laundering bitcoin: you send in bitcoins and specify a return address; bitcoins from other participants will then be sent to that address. [source] While US cryptocurrency exchanges must keep identifying information about their customers, it is possible to anonymously buy cash at dark web marketplaces with bitcoin. [source]
Tether, a centralized cryptocurrency pegged to the dollar, is often used to buy or sell cryptocurrencies. It is controlled by bitfinex, the largest cryptocurrency exchange. It claimed that it holds $1 in cash for every Tether mined, but later admitted that this was not true. In 2017, bitfinex drove up the Bitcoin price by buying Bitcoin with Tether. [source]
Price manipulation schemes that are illegal when applied to stocks are legal when applied to Bitcoin.

Miners ultimately set the rules and will resist rule changes that aren't in their interest, e.g. replacing proof-of-work by proof-of-stake.
Miner cartels may form. Once a cartel achieves a majority of mining power, it can change the rules in their favor or seek rent in other ways. This is known as a 51%-attack. Such a cartel could also start a double-spend attack and thereby create a final large windfall before destroying the network.