I think part of the intention of the Second Amendment is to have a well-armed population that has the capability to push back against a government that has overstepped. Five or ten rounds isn’t going to help much there.
The need for a magazine is close to zero, but if you need one, you probably need, or would have a significantly improved outcome with, a 10+ magazine.
The number of people who have used 10+ round magazines for self defense is greater than zero.
Used, or needed?
Both
Who cares? It is a foundational human right. I don't have to prove my "need" for freedom of religion or speech, or right to bear arms.
Why is it a foundational human right? Who decides that? It seems to me that a lot of people disagree.
Human rights only exist because enough people believe in them. All of them, including free speech are up for debate and constantly need to be defended.
I don't know anyone whose house has burned down. Should I cancel my home insurance?