StackOverfow is great for questions that are very basic for people who work in the corresponding domain but can take some time to put together based on the docs along.

For example, "how to insert multiple multi-columns rows dynamically using psycopg2" It is trivial if you are writing sql everyday but may take longer to find the right postgres docs. StackOverflow gives you the answer in 5 minutes: several variants with different tradeoffs (readability, performance, security).