Roscop, the reason is traditional growing has plants in rows, to make weed control easier by hoeing, and because it’s quicker to sow seeds in lines than popping them in equidistant holes. Also it’s maybe easier to support a line of beans compared to equal spacings.
In veg gardens we can raise most plants in modules and plant equidistantly.
There is a huge range of possibilities between these two approaches, depending on crop etc.
