Bitcoin is trustless, you don't have to trust anybody*
* You only have to trust a bunch of chinese anon dudes that for all we know are pretending to be different pools so they could attack the network right now.
The concept of trust needs definition, I see. In all trade, you need to trust the other party. If you buy an apple, you have to trust the seller that the apple is not rotten inside, or if it is, that he will replace it with a good one when it is discovered. If you pay with a carrot, the same thing. You can not avoid trust. In an evolutional view, when an individual can remember and identify another individual, is the breaking point. In trade, generally, the possibility to develop trust between members of the trading community is a big plus. Between people who trust each other, trade flows easily.
Then there is a distinctive trade, it's beginning and it's end. If a trade is concluded successfully, there is no more need for trust. Now the trust that is achived is good for future trades, but the concluded trade is finished and there is no outstanding liability.
When money is paid, the trade is concluded and there is no liability. If the trade is paid with debt in any form, there is remaining liability, either between the traders themselves or a third party. This means that if a trade is finished with payment in fiat, gold, or bitcoin, it is concluded, there is no liability that needs trust. If it is paid with a bank transfer, a credit card, a bill of exchange, there is reminescent liability somewhere in the system, and the need for trust that some debtor is able and willing to clear.
You need to trust the exchange, but only until you have withdrawn the bitcoin or fiat you converted your money to. After that, no trust is needed.
This is a huge difference between holding bitcoin and holding fiat in a bank. Bitcoin is trustless, the deposit in a bank account is not.
