Can't the four edges of the table style be controlled separately? But why are there four codes?

I didn't understand this, what's the unique usage.
I thought it could be set separately, but always with the last one unifying all four sides.
 

tabSty.properties = {
//topBorderStrokeWeight: '0.1mm',
//leftBorderStrokeWeight: '0.2mm',
//bottomBorderStrokeWeight: '0.5mm',
rightBorderStrokeWeight: '0.5mm',
}