Yes, by switching from use to require and import, you are reducing start-up time and probably reducing memory utilization (unless those modules are getting required elsewhere) until that chunk of code actually gets run.

The only thing you are losing is that the import doesn't happen until run time so any imported subroutines are not predeclared before the code that uses them is compiled. The practical consequences of this are that

• you'll need to use parens to invoke the functions and
• for any functions with prototypes, the prototypes will not be in effect for your code.

For most modules, those two consequence are pretty minor.