"Not perfect" and "has a small impact" aren't the same. If condoms had the same failure rate in preventing STDs/pregnancy as the COVID vaccines do for preventing infection, we wouldn't use them. Luckily, preventing infection isn't the only goal of vaccines, so it's still worth getting for the protection from severe illness and death.

> If condoms had the same failure rate in preventing STDs/pregnancy as the COVID vaccines do for preventing infection, we wouldn't use them.

No? If they were the best form of contraception we had (which is the relevant comparison w.r.t. vaccines), of course people would use them! It would make abstinence marginally more appealing, of course, but there are already people who don't want or can't afford a pregnancy who unwisely choose to forgo contraception. There would certainly be an enormous number of people who would choose to use condoms rather than forgo sex entirely.