It’s not just policing the grass. You have to be ADA compliant, you can’t have inclines too steep, you need sight lines with other traffic. There are many reasons a path is created somewhere.

Just look at the picture below and how the desire path could end up hurting the tree roots. You would also have a decreased sight line with traffic coming from the right.

https://en.wikipedia.org/wiki/Desire_path#/media/File:Desire...