I prefer the V-neck versions which are difficult to find right now but it seems to me that the crew neck versions are much more "in" right now -- because crew neck everything is in?
I tend to look awful in crew neck tops, due to short neck, buxom body, missing waist etc etc. I do like putting a crew neck cardigan over top of a crew neck tee or blouse, worn open to create vertical lines that I tell myself are more slimming to the eye.
I also like crew neck cardigan buttoned just at the top most button, the rest worn open, over a flowy blouse.
I have a basic black crew neck cardigan with gold buttons permanently packed in my laptop bag, for work.
If none of the great ideas here appeal to you, and the cardigans are in great condition, then I advise to tuck them away for now -- don't get rid of them. This is a classic that comes back around frequently. I've got a bunch I'm not wearing but I've held on to for same reason. The V-necks, OTOH, all got worn to shreds.