Yes, RVD brings something the rest of their roster doesn't. He's very popular across the groups of fans. He's a talented in ring worker. He is exactly the type of veteran TNA needs. Popular, talented, believable workers who have cred as something other than a failed WWE project or a WWE reject. If they can't think of good things to do with RVD, they are stupid and deserve to go out of business.
Edit: Daniels, AJ Styles, Samoa Joe are three very good workers who have no real mainstream appeal. RVD is more popular than any one of them. RVD is much more vaulable than a guy like Flair at this point, because unlike Flair or Booker T, or even Hogan, RVD isn't washed up or rejected by the E. He's insanely popular and has always had a cult following. He's a guy that common fans will be like "Oh he's in TNA? That's cool!" as opposed to "What? FLair is still wrestling? LOL!"