Looking at the diagram in #1, it appears that scientists aren't quite sure how it works, or there's the possibility it might work in more than one way. There are several ways they think it might work to prevent fertilization, it appears.
Although of course using a dependable contraceptive and reduction of casual sex are both preferable, I'd think one emotional advantage of the morning after pill would be that the woman wouldn't know at that point whether she was actually pregnant or not.
One of the emotional advantages of the NAZI gas chambers was that those who were doing the killing didn't have to be so close to the people that they were murdering. The earlier method of shooting each individual in the head took a tremendous emotional toll on many of those who committed those crimes.
Cordially,
This is the moral equivalent of "I saw the bushes rustling and I fired into the bushes. I'd prefer not to know whether there was a human being in there."