There's always a reason ;)

Being a self-hosted product we have to make tradeoffs for the thousands of people operating (scaling, upgrading, configuring, troubleshooting...) instances. In short, we try to keep the system architecture fairly simple using available technology and keeping the broad skillsets of admins in mind.

It was a somewhat difficult call to add ElasticSearch for it's broad search capability, but being used for other purposes helped justify it. Adding Hound or similar services that were considered would have added more to administrative complexity and wouldn't provide for a broader range of search needs.

We continue to iterate on search, making it better over time.

A fair point, but I will just say that Hound is _astonishingly_ low maintenance. I set it up at my current employer like two years ago and have logged into that VM maybe twice in the entire time. It just hums along and answers thousands of requests a week with zero fuss.