I guess it's like people in 200K sports cars capable of 300km/hr cruising down Bondi beach at 40km/hr.
Personally I think women wear this stuff as it's comfortable, I get around in shorts and t-shirts 90% of the time, if it's cold it will be shorts and a jumper, it must be around 0 degrees for me to consider abandoning my shorts.
Why?? Because it's comfortable.
Going out?? Jeans and Polo shirt, as soon as I get home back into shorts....