I was thinking that the game could be more realistic and organic if the modders make a mod that changes the world generation and remove the straight cliffs to a tipe of hill. it would be more smooth and more realistic look!
I think the blockiness makes it a lot easier to mine and build, as well as offering an interesting aesthetic. It also offers natural walls and choke points, which I suppose is both a pro and a con, but I think is mostly a pro.
Part of the reason for the change was also the way the engine works/worked. It had regions, which were basically collections of cuboids or something similar. If you had nicer gradients, that meant more regions, which meant less optimization could be done, and more memory was required to hold the (more complex) structure.
I think ever since then, major improvements in the performance department for that have been made, so it might not be an issue anymore - but since then, all systems have kinda been designed with these levels in mind.