Since the birth of Thunderbolt in 2011, Apple has begun phasing out Firewire. In late 2013 most of the new Macs were only equipped with Thunderbolt with only the Mac mini with a Firewire port.
Thunderbolt is faster simplified technology. But many users who upgrade their Mac will still have all of their existing Firewire products, docks, harddrives, audio interfaces etc. This was a problem that for a short while had no solution.
Problem solved. The Apple Thunderbolt to Firewire adapter enables you to easily connect up to 63 externally powered FireWire 800 devices to your Thunderbolt port-equipped computer. The FireWire 800 port even provides up to 7W of power for your bus-powered external hard drive solution needs.
So go take a vacation with the money you were saving to upgrade the hardware. Take a sigh of relief and go buy the Apple Thunderbolt to Firewire adapter so you can still use all your gear!!