I never got chickenpox as a child despite going to chickenpox parties, but did get it in my thirties from my children, it was awful, a raging temp that wouldn’t go down, vomiting, and spots the size of boils all over me, in my ears and on my eyelids. Took ages to recover.
My DDs got their little ones vaccinated as as soon as they could, cost a lot of money but I reckon is worth it, had a GS who got measles before he was old enough to have the jab, he was hospitalised and was dreadful to see the suffering he went through. After that DDs accepted any jabs that were available for their children.
The whole idea is to eradicate childhood illnesses, especially those that can be fatal like whooping cough or measles, but without parents taking up the vaccine for their children there will never be herd immunity.