Does it really require an understanding of the principles?

Very good question!

Maybe not.
If all you want to do is to light a fire using the same kind of implements as those gifted to you by your teacher … then no. All you have to do is to remember how to build a new set of implements when the old one is gone and follow the instructions. To a T.

But if you want to make one step forward… to improve the implements… to rise to the next level…