A thinner phone fits better behind a front pocket wallet.

Sure, but again comparing it to the SE, which I consider the better form factor, it's 1.7mm thinner. Unless you count the camera bump, in which case the SE is thinner.

The SE also have a small camera bump ~2mm, so 9.3mm max thickness, compared to the Air at 11.3mm. The Air suddenly becomes a chunky phone, especially if, like most, you put on a cover.