The weight of the material is supported by your shoulders, and not your hips, which is far more comfortable in general
In addition to having more room for pockets, overalls can carry heavier things without falling down, nor need for a belt
Since the weight of the material is carried at the shoulders, bending down at the waist is easier and less restricted. The waistband no longer needs to be tight, since it no longer serves a functional purpose
Yeah people are here talking in theoreticals but they’re literally worn for comfort. They keep you warmer in winter and allow airflow in summer. They are easy to wear with a toolbelt, back brace, or both. And generally, you only carry as much as you need to anyway - most people in the trades don’t walk around with a ton of stuff on them, they carry a bag or a bucket to where they’re working and go from there. Framers and roofers are pretty much the only exception.
Speaking as an electrician who used to frame and lives in the South. Overalls have a point.
OK but could you tell us more details about that need for airflow in your pants?
To keep cool?