The problem I ran into was that I needed to perform roughly 20 interdependent queries in a short period of time. At most, I could do 5 queries in parallel due to the interdependent nature, but I still ran into trouble with the database being slow.

In the end, I added Redis as a caching layer, which cut time-per-query down a few ms per request, which was significant in this case.

I can only imagine how bad it could've been if I had block for each request instead of using the asynchronicity of node.