you dont need that. Its a glitch buster. Was used mostly for Spektrum as they had lots of issues. But Futaba doesnt require it.
It was also used to help with High Power servos with older ESCs that had a weak BEC Circuit. Most quality ESC on the market now have a decent BEC. the only time is is really an issue now is when Mulitple Servos are used, o Lots of Lights, Winches, etc. The scale and crawler guys use External BECs for that reason. Also air RC as they use many servos.