It certainly leaves me thinking about the story after I'm done reading it, more than it would had the author tied it up in a neat little bow of an ending. It's more compelling.
I think that in addition to being more compelling, this kind of ending keeps the theme in perspective. It doesn't really matter if the girl is interested in him or not in the end, and in fact, I think it would cheapen what happens in the story if it was properly book-ended with the romance plot in mind. What seems to be more important is the comment on life in Israel: that this guy living a fairly normal, young life - thinking about how to woo a girl and score some weed - is also faced with the unavoidable tensions of global instability. The presence of arab-israeli conflict in relation to the borders closing and the court-case itself creates the incredibly visceral sense in him that the somewhat innocent romance that he's pursuing is steeped in a very real history of sadness and probable tragedy, and that the end-result is equal parts a future of laughter and lightness, as well as a need for strength and support in the face of great loss. The uncertainty of the romance equates the uncertainty of the future in general.