This is not to replace the "Normal Curved Path Tool" (you've described) but rather as a complement (You could choose between the two systems, with an icon, or a keyboard shortcut).How you would using it ? With spraying you couldn't build straight lines!
Well, everything that is not a straight line or curves.In which case of scenario it would make sense using it for a path system?
If you only have the "Normal Curved Path Tool", how can you make this ? You cannot !
But I agree that the "Spray" solution is not the only one. We have the "Vector-like"
A system where it is possible to stretch the paths to any type of shapes, could be fine. (Like what you can do with vector shapes, in Illustrator, image below).
Unfortunately this would be a little more complicated to create the shapes we want, but it works too.