They want to see visible signs that it's doing what it's supposed to. You might be content to just trust that everything is working properly and that it will let you know if there's a problem, but most people aren't like that. When you run a scan, you want to see confirmation that the scan is actually working and what the results were. There used to be a voice alert telling you that the scan had finished about 50% of the time, but that's disappeared as well. Sometimes it pops up a message telling you that the scan is finished, but usually it doesn't. Now, about 75% of the time, you get no information whatsoever.
When you ran a right-click scan, you used to get a progress window which showed the progress and when it finished, it would show if if found any problems or if everything was good (for what that's worth). This has been a bug in Avast for quite a while now.
