I like it, because it makes the transition to real sprites much easier. You don't have to support a TTY library and a GUI client at the same time.
Yeah it's nice - I'm tinkering with a game in similar style to roguelike at the moment and considered doing the graphics ascii-style for rapid development instead of making 3d placeholder art. It ended up being quicker to learn the basics of blender and go 3d immediately, than to do text first and 3d later.
I assume it's to let you represent the world with squares, like dwarf fortress.
IF you did it with the terminal it would be tall and narrow.