When I want to transform something using the dimensioning unit boxes, I don’t always want to do it from the left corner.
9/10 I want to do it from the middle.
For example a centred logo if you want to make it bigger and you work precisely, you use the dimension box to increase its size and the logo is no longer centred because the anchor point is always top left.
In adobe’s (and many other program’s) transform box you have a little dialog box that allows you to change the anchor point. Saves so much time.
Also for example for bottom aligning things precisely.