There are many benefits of using a trap/shrug bar over conventional deadlifts:
-The center of gravity of the resistance is in close alignment with the center of gravity of the lifter when using a trap bar. This enables the lifter to remain more upright and takes stress off the lower back, making trap bar deadlift a quad dominant movement as opposed to a hip dominant one.
-Your shins are spared using a trap bar.
-Trap bar deadlift works more musculature than its conventional counterpart, as there is more knee flexion, which then results in more muscle growth over time
You can read the full articlehere.