I was one of the data points in that spike related to the Chinese balloon incident though that is not the first time I used sondehub. A couple years before that incident I found the site while trying to help someone understand what they were seeing in the sky near where they live.
An old dopehead, friend-of-a-friend was paranoid that they were being surveilled by aliens in UFOs, something they could assure you had been happening since the 1970's. Not coincidentally I'm sure, that's when they were a young dopehead. While outwardly funny to most of us, it was a serious issue for them. To help them understand all the shiny things in the sky at night I assembled a list of tools that could help them rule out various terrestrial sources for the shiny things. Stellaris or Celestia could help them identify stars and constellations, even showing them what the sky should look like at their exact location so they could compare in real time. They could also use their digital camera (after instructions on how to take low light photos that show stars) to take photos and later compare those photos to stars and planets that would've been visible when the photo was taken. I pointed them at Flightradar24 and FlightAware for air traffic and recommended they get a license instead of the free version so they could track more things better. They weren't close to an active military base but using either or both of those could help rule out military air traffic when the pilots were flying and broadcasting ADS-B.
Since many UFOs in the historical record were blamed on weather balloons I looked around for a way to find weather balloons visible in your area and that is when I found sondehub. The ability to see the balloon track was especially useful since I explained how objects at high altitudes could be visible even if they are hundreds of miles distant when you have a clear line of sight so the balloon doesn't need to be between them and the horizon. It only needed to be visible above the horizon and using the tools they could rule out quite a few things. Around the same time people were posting great photos of sprites associated with powerful thunderstorms well over the horizon so this helped them understand that shiny things in the sky are not necessarily close to them. I also used HeavensAbove to help them track known satellites and the ISS. Having them see the ISS cross the sky at their location a little after dark helped them understand why a bright light crossing the sky can quickly disappear once the concept of the earth's shadow was clear. It was nice and bright while sunlit and winked out as soon as it passed into shadow. I gave them links to astronomy sites so they could know when to expect meteor showers and other celestial phenomena.
All in all, they got a nice collection of tools, freely available, that they could use to understand why there were sparkly, shiny things in their sky. I haven't yet had confirmation that any of those sparkly, shiny things could not be explained using those tools.
Thanks for this link.