The only "real" con for me is the resale. To be honest it isn't that big a deal either because it still has a LOT of seat post and 4cm can be added with spacers if anybody were to need more. IF the person needed another 15cm on the seatpost then I'd think they should be riding a 60cm frame not a 56. Or maybe if you were going to grow forever.

Pros for me? Looks, comfort, stiffness, aerodynamics and not having to align the nose every time I have to move it.