It's obviously a good booking choice, since Del Rio has always been booked by WWE to be a notch above the average mid-card worker and always at least a second row contender for the main title. He doesn't have anything valuable to do right now since he's not in the Elimination Chamber or any title picture right now, so why not feed him to Batista?
The fans are still not 100% on Batista's side - especially not as a face - as many still feel he is responsible for Daniel Bryan not being in/winning the Rumble; I guess the quite audible boos for Batista when he came to Dolph Ziggler's rescue this past Monday on RAW show that quite clearly. So obviously, WWE is trying to get the Batista train on the right track for Wrestlemania, by pairing him with a very good and safe in-ring worked in Del Rio, who will serve perfectly as cannon fodder for Big Dave's machine gun entrance.
The match probably won't be anything spectacular, but I also expect Batista to completely annihilate Del Rio in the end, gaining the momentum he needs to not be booed completely out of the building at Wrestlemania (which might happen anyways, if the main event indeed remains Batista vs Orton, with D-Bry nowhere in sight).
I think pairing Batista with Del Rio here is especially smart since Del Rio should be able to carry Dave to a very solid "comeback match", probably make him look better than he really is at this point (considering his ring rust), which might make him more appealing to fans as the focal point for WM30. However, I still think WWE needs to go with a Triple Threat between Orton, Batista and Bryan at WM, with Bryan going over. Only chance at this moment to get that huge "feelgood" moment that would be fitting for Wrestlemania 30, in my opinion.