You also get an idea of what company cares about and if its a good match for you.
If you move to next step you did something right, if not then there are others that have done better.
Ghosting might be a problem like someone forgetting to process stuff, vacations, etc, just check with recruiter whats the status, dont be antisocial.
And if it took you 6 hours to do, you chose to do it, and hopefully you learned something. There is no implied obligation on other side to pursue you just because you took on challenge.