So the column when lowered sticks down below the base and surface of the stand? If that is the case and if the column has a key slot running from the bottom to or nearly to the top and an anti-rotate key that runs in the slot, then yes, that would be an improvement over a normal drill-mill.
The main drawback common to all typical drill-mills is that you cannot adjust the distance between the head and the table without losing your horizontal location. With a standard knee-mill, that doesn't happen. It isn't normally done, but with a knee-mill, you could drill a hole by raising the table instead of extending the quill. So you could, for example, drill a hole deeper than the quill travel if you needed to.