I edited the post and added an image in the same post. ^^
The “problem” is not really a problem, when you be a godlike fantasy warrior that can slash all and everything. xD
But imagine the following: A big wall is in front of you, like 100x100 meter, you attack at the bottom and the complete wall is sliced, no matter how high or wide it is. ^^"
I think the best usage of the slice is for small objects like barrels, trees, ropes, chains and so.