I prefer it because it seems more honest to me. While there are many people who will avoid, e.g. discussions of rape, because of triggers, there are many more who will choose not to engage just because it's a serious and depressing subject that not everyone wants to talk about all the time. On the other hand, some people will look at TWs/CNs because they are interested in a specific subject, especially in fic or art. Thus, content note seems more accurate to me based on the way people actually use TWs/CNs, since it encompasses all the common ways people use them instead of just the one.