when the CC stuff came out one of the things that was mentioned as a benefit was Bethesda's QA processes that would ensure that CC content was tip-top and totally integrated with your game, because they're a pro development house and have such amazing QA processes in place that capture so many bugs before their content is released to the public (ahem).
Sadly for everyone, this QA process didn't really work out all that well, and as a result, so much CC stuff broke the game.
The Tunnel Snakes mod, for example, somehow broke the first quest you do with Codsworth, where he searches Sanctuary with you and kills the flies. Quality QA right there.
That settlement raiding thing was literally a whole series of flaws and broken code stuck together with vinegar and brown paper. So bad. So, so, so bad.
They may have fixed the bugs in these things now, I know not because having suffered through Tunnel Snakes breaking the first quest in the game, I decided to do the decent thing, and throw the lot of it away.
I know they make some CC stuff free from time to time, but honestly, even free it's overpriced.
Save yourself a world of pain and avoid it all. You can get mods that are better supported and better made than the garbage on the CC site.