I agree it's still useful as far as creating the same curve as you said for ovals and any other track. The problem lies in not knowing at all what angle to the previous curve/straight the new curve is.
Here's my issue... Front stretch is 600m long. Turn left 90 degrees (63r @ 100m). Straight 400m. Turn left 90 degrees (63r @ 100m). Straight 600m. Now at this point, you can visually see that two 600m straights are not parallel (toed in, if you will). Ok, so change it to 64r for less angle. Delete, delete, delete, start from the front straight at 64r's and now I have a toe out.
As you can see, the two equal valued corners are not creating parallel straights as I'd assume. To make it work out, I had to mix 64 and 63r to make things parallel. The only way to hope for a 90 degree corner is to just draw it and try to line it up with the edge of the previous straight, but that leads to the above issue.