Why are there so many rebuilt titles?

I'm looking at buying my first q50 in the next few months and there are several clean looking examples in my area for reasonable prices. BUT they have rebuilt/restored titles. First off why are there so many? And Secondly is there any reason to stay away from them? Is it just a repair that the insurance wouldn't cover or where they most likely thrashed? I know there isn't a perfect answer but I'm curious if there is a q50 specific reason why I should stay away or not be worried.