Yes, this is indeed strange for me, and, I would guess, most people (people not from the US). The only reason I even knew cake mixes exist is because a former Au Pair told me about it, years ago. Apparently her host family was shocked when said Au Pair made cake the "normal" way, i.e. with eggs, flour, sugar etc.

Baking cakes from scratch is easy. Even I could make an apple cake very quickly with a recipe (I quickly found one online, but I could as well just have used the recipe book from the bookshelf), and I had a nice cake ready shortly after, never having made an apple cake before. My wife said "I don't have the time, you do it". And I did.

Mix? Full of additives and whatnot, I bet. I won't eat that.