"Why do you use that?"
I've been running front rack & panniers only on my commuter/light touring rigs for 5-6ish years.
It started to:
1) get my gear off my back during hot summer commutes
2) because my commuter was/is a fixed gear I didn't want the weight over the rear wheel.
It's become my preferred way.
I even ride single track with the set up.
Some people don't get it.
Some people don't like it.
And some people call it just a fad (I don't get that one).
But that's cool.
It's not your bike & you don't have to do it.
Run whatcha brung