It's one of the features that those in the MI industry struggle to appreciate yet those in the pro audio industry demand because of the usefulness. I'm pretty big on interfaces, I like to include as many tools on-board as I possibly can so that when you are out in the field you have the ability to accommodate a variety of needs, expected and unexpected. Yeah, it costs a few dollars more, but when you really need the feature to bail yourself out of a bind, the value is priceless.
I will be using my DI today for a local town festival stage where I will run ampless. I'll most likely use both of the XLR, one for my ears and one for the general PA. I'm crossing my fingers for a stereo mix-minus that I can blend with the DI signal. If thats the way it gets hooked up I'll be turning the master knob with reckless abandon...just because I can.
I definitely appreciate all of the outputs, as I've used them all at various times. They are way more valuable to me in a pro environment than things like Aux In for practice.