Deadlifting with proper equipment will help improve lifting mechanics, training specificity, and safety.
Lifting mechanics refers to joint angles, muscle activation, base of support, center of gravity, acceleration and bar velocity. High quality lifting equipment will optimize all of these factors during training. For example, using a deadlift bar allows a sumo stance lifter to use as wide of a stance as needed without the worry of the plates hitting the feet. In addition to this, the flexibility of the bar allows the lifter to get in a better starting position. The thin diameter and the better knurling of the bar enhances grip strength for the lifter.
Training specificity refers to the exercise being specific to the goal. For example, a competitive powerlifter will deadlift in competition, so he must train the competition movement. The equipment used in training should match the equipment used in competition as close as possible. This will increase the lifters confidence and familiarity with movement patterns.
Safety refers to the risk of injuries associated with deadlifting. There are certain types of equipment that can reduce the risk of injury when used correctly. For example, a trap bar deadlift may be safer for beginners or people with back problems because it allows for a more vertical back starting position which puts less stress on the lower back. Also, bands can be used to warm up for deadlifts and increase mobility which will reduce the risk of injury.