yeah but you couldn't lift that weight *without* the straps, they definitely up your max dl by a fairly significant margin.
who can't do 315? that's like just barely above novice weightlifting levels.
The real reason I use straps is I don`t like gloves at all and straps keep my hands intact. I got tired of bloody hands-pointless. I even used to use a towel on the bar. I never liked gloves as I found they gave me less grip because my hands slide around the bar etc and I feel I don`t have a tight grip with gloves.
When I do Dumbbell Bicep Curls I use straps as well. It does nothing for the lift, but I like the way it feels on my hands and the weight is really glued to me and I find you can get a much better flex and feel with the weight. Try it. Its a night and day difference.
Anyways, I deadlift the same amount, straps or no straps. One just saves my hands.