Yes, Blockchain is always described as “trustless” but it doesn’t actually eliminate the need for trust. Traditionally, we had to trust banks to verify transactions. With blockchain we have to trust the technology itself and the developers who design it (e.g. Vitalik Buterin arguably figures as a central authority. When the DAO was hacked users asked him to respond, which shows people still want to a central authority to appeal to if something goes wrong. The fake news he died caused US$4 billion dollars to be wiped off the value of Ethereum, which shows when people thought ETH’s central authority was lost, many lost trust in the network). In the case of ETFs the trust issue is even more complicated as we must now trust the manager of the fund as well.