I'm not sure why there's "literally no reason to trust" the results unless they report by precinct. It's an arbitrary consolidation of ballot types for fairly technical purposes.
Well, none but "oh, I suppose they have checks and balances and people from both parties working together".
The release of local results serves to allow everybody to see that they make sense and are plausible. Nobody's going to be able to guesstimate whether Multnomah should have given Barack Obama 66% or 70% of the vote in a close statewide race to the point where he can call out a result as obvious fraud - yet that's a 15k vote difference.