Uses for quarter blocks would be:
-More creativity: including more detail for curves from a far distance,
-new styles for windows, walls, floors, ect. ,
-If stacked only 1 quarter high, shorter steps for stairs, creating unique walkways
-If stacked 3 quarters high, used to jump over
-Creating gaps in the floor but still being able to walk on. Example, using 4 quarter blocks stacked up on the left side of the normal block space, but leaving the right side blank, creating holes in the floor, but not falling through because the gap is too small...there are many many things people could come up with.
The list goes on.
I have many more uses for it I could think of as well.