I hope it does not look almost the same. When set at -540, it will be discernible better (unlike in the pic above) and gridlines step will be smaller - so it we be possible to judge the average/max level of a dd in a certain period better.
On a second thought, I realize that if maxDD is very small relative to the total eq range, then indeed - as you say - such slight magnification will hardly make a significant difference and ColorEquity=0 is the way to go.
However, in most situations during development the relation is smaller and such suggested automatic scaling will be enough out of the box.
Ideally, the profit and dd should be scaled separately: fixed split of the chart space - 80(profit)/20(dd) , profit axis is from 0 to +(Y+15-20%) , dd axis scale is from 0 to - (X+15-20%)...both will be clearly visible, guaranteed
That's how other trading sw does it.