Filter Function with numbers and empty cells

I'm puzzled by how excel I handling the following situation. I have a column of numbers and empty cells (not blank cells, they are filled with "" - side question what is the correct term for such a cell?). When I use the filter function to return cells that are less than a given value, the "if_empty" value is returned if no values are less than the given value. However, if I use greater than, the "if_empty" value is not returned. See attached example. 
Why is this?