Many of the guys from Supraland run without them, but I decided to spend the extra time, trouble & money to install one in my Supra's fuel system.
As you say, it dampens the hydraulic pulses from the injectors banging open & shut, so IMO it serves a very useful purpose. Anyone who has quickly banged a faucet shut in their home and heard the pipes rattle throughout the house, can see the value of having one of these. Personally, I wouldn't run without one.