Do you provide with Sass/Less?
Possible Answers to Your Question:
Unfortunately no – Layers is designed to stay in line with the WordPress core and tries to keep a relatively low skill ceiling to ensure developers can create themes and plugins easily. Once SASS/LESS becomes more standard and WordPress begins using it, then we will likely move in that direction. For now, it would close the door to too many developers without those skills (even though it aids in speed and development in the end.)
You CAN create a child theme that uses SASS/LESS.