Wire leader are essential for much of your tropical and also Pike fishing. This black 7 strand plastic coated wire is perfect for such occasions, and coming with 10 crimps you are ready to start making some rigs straight away.
When fishing vertical is some tropical situations, wire can be used to make your assist hooks, and again this is fine for this too.
Nothing to do with fishing but I use wire leader for rigging on the working models of working craft of the eighth and nineteenth centuries. Far stronger than needed but the right size. I have rigging up to twelve years old and still sailing!