If you look at the documentation for any CPAN module, you might find that it supplies a lot of subroutine definitions that you really don’t want in your code.   Or, you may simply want to refer to a particular routine or set of routines, and to clearly document to the Gentle Programmer who will one day follow in your footsteps just where those routines are coming from.   This syntax uses the specified module, but then only exposes to view the subroutines that are named in the list ... not all of the subroutines that the module might contain.   And of course, in so doing, it explicitly identifies the origin of those routines ... which, BTW, is tremendously helpful in understanding unfamiliar-to-you code!

See:   perldoc -f use