I really don't see why the team needs this. There's been significant turnover from last year and a lot of new faces are going to be in camp already. Plus, there are plenty of prospects knocking at the door too. I rather see the coaching staff work with players already in the organization than give another lost soul a tryout. I just don't see the need.
And someone should edit the title of this thread--nowhere does it say that the Rangers are one of "many" who are giving Malone a tryout.
The coaching staff WILL be working with the guys already in the system. Malone is 34, he's not going to be looking for coaching (nor, I'm sure, would the coaches be looking to invest a lot of time with him). He's just looking for a shot to show that he still has something. Guys like that, you hope that they bring it 110% each day and increase the overall intensity of camp.
You're right, there's no "need" for this. There's no downside though. It's something you do because you can and because there's a chance you get lucky with a guy, and the worst that can happen is the guy sucks and you send him home.