They're cheaper for the same internal specs, so you save money if the extras you get with the Pro aren't compelling.

exactly, outside of pricing. I see people say Air is noticably lighter, but I may then have a heavy hand because 13 air and 14 feel almost the same in weight to me, unlike OG Air which was light and thin. Hence, why buy Air? it's not even smaller.

No noise, no dust inside, lighter.