@bythewell - It's not as simple as that. For one thing, the placebo effect is a real thing, so it's not completely useless to offer a patient a medication even if the medication probably isn't going to directly help them.
For another thing, often what will happen when a person has a viral infection is that the area will be more vulnerable to bacterial infections as well, which, of course, make the sickness a lot worse. So it actually makes sense to give someone antibiotics for prevention of something that is actually pretty likely to happen.
And finally, the super bugs are caused more by people who are prescribed the right medicine but don't take it properly. If you are given antibiotics you really need to take the whole course, not just take them up until you feel better.