I'm not really sure what you mean here- isn't grinding for grinding's sake just another personal goal/intrinsic satisfaction?
Other than that I think I basically said what you did:
The best-lazy way to gear is just the 3rd set of tomestone gear.
The gear is literally useless as once you have all BiS, you've already finished all the content except MAYBE Ultimate. There isn't some larger additional content that requires even remotely close to BiS.