The sliding-wall issue is not exclusive to walls, though. It also affects things like
lava. And I don't want to be lazy and resort to using the tileset whenever TWBT has a bug with displaying something.
On the other hand, there is
one thing that I will absolutely have to use the tileset for. Earlier, I was experimenting with liquids and I was mortified when I found out how you overwrite them. If you go into DFHack, hover over a water tile and probe it, you'll notice that it never says "water". Instead, it identifies the tile as something like "Open Space" or "Constructed Floor".
This means that when a tile is filled up with water, it doesn't change its type to a water tile. It just changes the ASCII graphic. So in order to override all of the water in the game, you'd have to create graphics for "soil displayed as a water tile" and "grass displayed as a water tile" and "mushroom cap corner as a water tile". And there's no way I'm going through every item and tile in the game and giving it a submerged graphic, so I guess I'll just have to use the tileset for that.