The Air is noticeably lighter and much easier to throw in a bag without thinking about managing weight. The Pro is a fine weight for commuting, but for traveling longer distances, the weight definitely makes a difference. To the point where I'm seriously considering setting up a work partition on my personal machine so I don't need to lug the pro around on an upcoming trip.
As for the screen, I think "gimped" is not doing it justice. I regularly use both, the Air's is a very nice screen in its own right and while there is a difference, it feels more like a relatively small increment on something already very solid, at least to me (I don't do any pro photo/video work). Same for the other differences, the Air's speakers are already pretty good, connectivity is fine (for me), I like not having a fan, it's way powerful enough for what I do.
Gosh having started program on 286s in the 1980s, my M1 air feels blazingly opulently fast. What sort of local development are people doing that requires heavier compute than an M1 air, but doesn't require a full on cluster?
I imaagine that the lubricant in the fan will still age, but that is also going to be less of an issue because of less dust contamination.
Apple's "Pro" branding has become increasingly meaningless but in the MacBook category, which I believe is where it originated, it's meant to suggest "media professional", a demographic which has reason to care about all of these things.
There are even shades of this in the iPhone and iPads Pro, which have a few features which are mainly of interest to professional media types. For AirPods it just means "the expensive ones", and for Vision Pro it means "this is expensive". That's the main signal for phones and tablets as well, realistically.
Surely you mean “more noise”.
The Air is also way overkill. I had a 12" MacBook before that. It ran the software that I wrote. I write markdown in Sublime Text and run python scripts.
There just isn't a reason to get something beefier.