Let me ask you this then....what's the difference between "parking lights" and GM's "daytime running lights", which on many of the products (Cadillac CTS, STS, etc) was just an illuminated turn signal all the time, just like parking lights?
Usually, I turn them on to illuminate the guages, it's still light out and people are able to see me well, otherwise, as I said, I'd turn all the lights on.