It seems to often make it hard to get back where you were, like you go west and then east and end up in a different place. I don't know enough about z-machines to tell why.
Newer games also tend to follow some quality of life rules in their design, things like avoiding arbitrary deaths and avoiding situations where the player cannot progress because they missed something earlier in the game.
Anything Non-Zork. Even Adventure from Don Woods was half-consistent in some places. But having an "odd" geometry matched perfectly the environment of a cave.
On the one hand, you could encode the hallway itself or the road curve or the passageway as their own weird segments in the grid. But then maybe you bog the player down in a lot of liminal spaces that don't really add much to the game. On the other hand, you could ask the player to bring or build their own map and pay attention to descriptive text like "to the north is a passage that seems to bend to the east" or far more subtle variations of such.
Zork and many other IF games were built on the premise that people would map things and getting lost or confused by grid breaks was part of the fun. (Going back to, as neighboring comments point out, the original Adventure which was modeling caves and caves have always had strange three-dimensional twistiness that doesn't fit a square grid. Part of the fun was discovering that disconnect between the game mechanics using square grid compass terminology and the digraph of the game spaces being more confusing than that.)
Instead imagine that "GO EAST" takes you onto a winding road.
The road arcs southward and to go back you'd have to "GO NORTH".
Further... some travels in Zork even drop you through a hole (though I forget if it tells you so).
So going East might put you in the basement and there's no way to climb back up.