Because no man is an island and trust in institution is how our society evolved. Trusting that when I buy food from market, it is safe to eat, trusting that when a sentry says the enemy is coming, that we prepare. Sure, they fail at times but it's vastly superior to the alternatives.

I don't get this notion of 'trustless' as a feature. We should want to trust more. 'Do your own research' is such nonsense in so many ways - I don't want to re-invent periodic table or the that the Earth is round. Sure, the experts can be wrong at times but for one to challenge that, one has to first be an expert in the same domain.