[nytgop77]

One more angle: reliable & internalized abstraction vs unfamiliar one.

Java string is abstraction over bytes. I feel I understand it intimately even though I have not read the implementation.

When I try to understand code fully (searching for root cause), and there is String.format(..), I don't dig deeper into string - I already am confident that I understand what that line does.

Browser and linux api I guess would fall into same category (for others).

Unfamiliar abstraction even with seemingly good naming and documentation, will not cause same level of confidence. (I trust unfamiliar abstraction naming&docs the same way I trust weather forecast)