The second point is that "need" changes. Today is a warm sunny day, so I don't "Need" a coat. Within a day or two that could change, and it could change dramatically enough so that having a warm coat could possibly be life saving.
When politicians and anti-gunners say "you don't need an AR", they are arguing that we don't need a coat because it is warm outside. What if the political climate drastically changes? I am a big fan of the 12 gauge for most of my defensive purposes, and as I sit here today I don't "Need" an AR. If the political climate changes enough where I could be killed or imprisoned for my faith, race, political views, or some other unconstitutional reason, having an AR could be just as life saving as having a warm coat in a blizzard. Personally, I believe that anyone who does not prepare for bad weather is foolish.
