Vaccines were developed to protect us and save our lives.
Thousends/hundred thousands of people worked on getting cure to certain things. And now we have today's vaccines, which work pretty well.
Science has never been perfect, and science can't cure everything perfectly, however it is much better than literally nothing.
Yes, there is a type of vaccine, you get it when you are a child, when you get infected with weakened desease, so you can prepare for it when you really need the protection.
So in a way @Leatherface your point is not valid. With certain vaccines the body gets desease, which it cures, and later it can't be infected ever again with same desease.
In other way you are right, that the body should have a strong immune system that you develop from getting sick and winning that battle against intruders. Sometimes we can vaccinate, sometimes we not. Vaccines are good against certain thing, not against everything.
So in short. Vaccination is necessary especially for young children against serious deseases. Also can be for adults. They are not the perfect and ultimate solution, but far better than nothing. And they don't cause autism...
So that was my opinion about vaccines are good or useful or not