Abstinence does not have a significant benefit above another method of contraception.
Of course it doesn't. That's why we have those new methods. The only "benefit" of abstinence is that it is "right" from the Church's POV. If you don't care about that (many don't), then there's no point in debating about it.
For me, it's rather simple. You either listen to the Church, and in that case you should actually practice abstinence until marriage, or you don't and use a condom. Anything else is foolish and dishonest, if you don't use a condom "because the Pope says so", but don't listen to him on the matter of extramarital sex, then you're dishonest with both yourself and the Church. It's common stance, but people who do that only lie to everyone around, including themselves. Either denounce the Church, or stick with what it says.
Teenagers are going to have sex, but for them, whether Pope endorses condoms or not is rather meaningless, because let's face it, most teenagers don't give a fig about what the Priest says, and only go to the mass if the parents force them. Any changes to Church policy on sex should be considered in context of gaining those teenagers back, not actually altering their behavior, because the Church hardly has any say in it anymore.
