Not to do with darks. I’m using the same darks for my camera that I’ve been using since the beginning of last year. I have a library of darks for each exposure that I use and I never scale them. CMOS cameras generally have much lower read noise than CCD cameras so stacking loads of short exposures works well. This has benefits in the stacking process since outliers (satellite trails, the odd badly guided image etc. can get rejected in the stacking process. You are right that CCD sensors are becoming specialist items now limited to a very few applications. Even cameras on spacecraft are gradually making the transition.