I spent a lot of time trying this with PSB, and eventually gave up. Several forum members worked on a variety of avisynth scripts, but in the end the result never looked as good as the best single capture. I’m not saying it isn’t a good idea, it’s just that you need to have some really sophisticated software to align everything perfectly.
I think in theory it would be good if you had at least three versions, and could eliminate the most disparate of the three (frame by frame), averaging the remaining two. That way you could remove noise. Otherwise, by averaging all the takes, you’re essentially incorporating all the noise from all the takes.
It’s also a very different situation depending on if you’re working with video or film.