It's interesting to consider the different aspects of trust, and how they work in blockchain-enabled environments. For example, the Steem blockchain allows me to see that someone has paid me what we've agreed, and vice versa - which is great. As you say, I don't need to give up any trust to a bank to mediate this transaction.
But when I make this comment, I have to trust that someone with massive SP and a higher reputation won't use their position demonetise my work and ruin my reputation. They don't need to trust me in that regard, because I cannot do the same thing back to them. If I have any protection at all, it's because I trust that people of relatively high SP will voluntarily back me up.