> Smoke test though, I can't say I've ever see irl usage.

We use it all the time at my employer, and have for decades. They're basic tests to tell you if the app is up or not.

Like: you go to this page, and it shows a big green banner if the app can connect to the database and its disk isn't full. If one of those basic things are wrong you get big red banner or you can't load the page at all.