Why do you assume that anyone who wants to have sex will be seeking out not only contraception, but an experimental, first-of-its-kind contraceptive?
I want to (and do) have sex and I never use contraceptives. Were I interested in curtailing the birth of my children, even before I was married, I would absolutely NOT use a drug that is brand new.
Ultimately this needs to be recognized as a convenience thing. Condoms are a very effective, extremely low-risk option. They require no modifications to your biological system and reliably prevent pregnancy (not to mention STDs).
Even drugs like "the pill", now old-school, put people at risk for scary complications that sometimes happen and significant undesirable side effects that frequently happen.
We all love science and technology and that's great, but drugs are risky, and effects are often not visible until they've been in public use for some years. There are a lot of really sad examples of this, where some widely-prescribed drug has a little-known side effect or misunderstood risk profile for some patients, and it can, and literally has, resulted in death.
One should consider the risk involved when weighing "Would I rather take five seconds to slip on a condom, or inject myself with this experimental and/or brand new drug?"
I'm sure there will be early adopters, but as someone who wants to have sex, there is no way I will be among them.
