Is there a benefit from one over the other? I know that there are a lot of strong opinions on this subject. Some are vehemently opposed to Kettlebell Swings because they "hurt your back". Others are also strongly opposed to Deadlifts for the same reason.
I look at it from a very different point of view. I strongly think that both are necessary, for both health and longevity reasons, in addition to being complementary to each other. A strong Kettlebell Swing will reinforce your Deadlift, and a strong Deadlift will reinforce your Kettlebell Swing.
I've been teaching for many years that the Deadlift is the foundation for all of the Kettlebell ballistics.
Why you might ask?
Because the Deadlift is not about how mush weight you can pull. It's purpose is develop the ability to generate a tremendous about of force into the ground and translate that into moving the bar (or the Kettlebell). A strong Deadlift allows you to feel the ground and use it to tie the biggest muscles in the body (lower body and lats) into the force production chain, as opposed to using the much smaller upper body muscles.
In regards to longevity: both are going to be key to staying strong and mobile as we age. If I was starting someone from scratch, I would no doubt begin with the Deadlift. But once they demonstrated competence in the Deadlift, the Swing would be introduced as well.
Like I said, everyone has an opinion about both exercises. Check out what Dan John has to say on the subject: