Not putting cws on triggering things just makes it so the people who need the cws can't engage with your posts at all
I need cws for some things (suicide, for instance). It lets me evaluate whether I'm able to deal with something before being exposed to it
Adding a cw is the thing that lets affected people engage with your post in the first place. Without them we have to mute the affected topics or just unfollow people who post about it instead.