My wife and I have had this conversation a lot.
A starter has a finite number of actuation in its life. Let's call it 20k starts over the course of its years and then it shits the bed. When you have 40 starts a day instead of 4 the lifespan is seriously degraded.
Now think about the copper, magnets, iron, and other stuff that needs to be mined, refined, processed, etc until final manufacture of this starter. All of this requiring workers to DRIVE to work. Then shipping to a warehouse. Then to a distributor or store. Then a mechanic putting it on.
I think any carbon footprint savings from fuel is going to destroyed 4x over when you are replacing these starters more often.