> You need a decent understanding of something in order to delegate it. ... if you have a choice or delegating two things, choose the one you know best,

I don't think that is true, even in general. In general, experts can figure out the details and get it done entirely without your help. My corporate taxes for instance. Or my furnace upgrade. Or my companies new data infrastructure ...

In the specific case of software development, this can often hold true because you are not delegating something to an expert, since it is new to everyone.