Off the top of my head, no. As much as I may think I think about efficiency, I think intuition is the best course for me, and for the learner. Set efficiency on the back burner and get immersed in the concepts without that constraint.
We saw in the example where the opening expression was zero, itself, and the case expressions were modulo operations. One satisfies the other. That's how this works.
Expressions are not statements, but representations. They present themselves by whatever construct is deployed and always result in a value.
a = b
is a statement. It is immediately declarative.
6 * 7
is an expression which in this form is meaningless, but if we assign it to a variable will be cached for later use. (We know all this ...)
Expressions are the backbone of dynamic logic since they make up the bulk of the input stream of our programs. Remember, there is an interpreter back there that sees them all, in their many forms.
If the expression passes syntax and exception muster, it will pass in a switch. That's why it is necessary to explore. Remember also, a function is an expression. If that doesn't brighten the picture, I don't know what else would.