DY
“Quite a negative thought to start a marriage with”
granted
Though more negative than the thought of the couple getting divorced and him being so spiteful that he just kicks her out on the street with no food or money? (keep in mind he gets to keep anything she earns during marriage, if not for the kesuba a divorced woman would be penniless. The KEsuba comes along and provides her even if the husband (or his yorshim presumably the children they may have together!) are to cheap to provide for her.
“In other words, it’s not designed to deliniate the … post marital obligations as a kesubah is”
It absolutely is! it is designed to get the wife her get once the marriage is over.
“One can argue that the benefits, preventing the malicious actions, outweigh this negative”
That isnt realy what we are talking about. I am strictly using this example to point out how based on “Daas Torah” people accept all sorts of (non-halachic, barely even hashkafic) nonsense simply because somebody chashuv said so