The objective of the indirect opener is to first get the target’s attention and then transition into a more natural topic off the opener. Indirect openers work because most people are open to have conversations with strangers and generally will not reject the PUA’s approach unless he comes across as creepy.
The advantage of indirect openers is that they do not put the PUA at much risk of getting rejected because they are not directly making any advances. They allow the PUA to “fly under the radar,” so to speak, and gradually build attraction with the target. They also allow the PUA to get to know a little more about the target before making his intentions known.
The downside of indirect openers is that, if the PUA does not eventually make an SOI, the conversation will end up being platonic. Some PUAs feel that direct openers are more genuine and that they screen out women who are not interested in a relationship.