This completely leaves out the considerably large group of people that do what everyone should be doing:
Weighing their risks against each other.
If you think your body can handle COVID, and you don't care about potential long term effects, good for you.

If you have a preexisting condition, like one in four Americans do, you might have a valid reason to look for every option available to prevent an infection, because symptoms can end up being severe and long term, up to getting killed. And that is true even if it's just a damn flu to you.

The vaccine can cause severe side effects as well, but there are differences: It's less likely overall compared to COVID side effects, especially the severe ones.
It's a controlled environment. The time frame is predictable, and it's a once-off (or twice) thing. Medical personnel will know it's a side effect from the vaccine and can go for more targeted treatment.
You don't have to be on high alert ever after.