People are very blasé about flu.
the last time I had flu (as a healthy, fit, 32 year old, running several times a week and in great shape) it laid me up in bed for over a week, and I was sick for weeks. Over Xmas :(
The time before that I had it, I ended up with pneumonia, very poorly indeed.
It's rare that they get the prediction for the vaccine so wrong - their success rate is remarkably good when you think about the scale of the challenge. Last years vaccine was not, however, completely pointless. On a population level, a few percent fewer cases translates to lives saved. It also reduced the severity of symptoms - that alone can save lives.
I would urge everyone, but especially pregnant women, to get a flu jab every year. You are not "putting harmful chemicals into your body" you are instructing your immune system to recognise an extremely nasty pathogen.