Well, I don't want to bore you... but ... yes, that's it.
My car has the ability to unlock with my phone, and it parks directly below me (apartment). So it drains my phone's battery via bluetooth 24/7 unless I'm plugged in all the time at home. Ex: My iPhone Air would drop 12-14% overnight if not plugged in because of my car.
And yeah, the Apple MagSafe Air battery doesn't bypass the internal battery so it was chewing through cycles especially when I used the phone with the battery attached throughout the day.
For a test, I used the Apple Air MagSafe battery on my 17 Pro Max and ... it does same thing - doesn't bypass the internal battery like wall chargers / other MagSafe batteries do. See below.
Example - a normal day at home
17 Air:
View attachment 2578585 (I used 2 cycles this day (plugged into car 2 times - MagSafe rest of day)).
17 Pro Max:
View attachment 2578586 (I used 0 cycles this day).
(The blip at 6pm was me using the Apple MagSafe Air battery on my 17 Pro Max to see if it would bypass, it didn't).
So warning to those using the Apple MagSafe Air battery - you're gunna be eating internal battery cycles at an accelerated rate.