How much would it hurt? It's one more cert in the pocket that could become useful at some point. Typically, its not a long class and the checkride isn't terribly difficult. Flight planning is flight planning and you might be surprised how much is similar to planning an XC flight in a piston aircraft. I took the class, did the written, but never followed up and took the practical. I really should have though, it would have qualified me for yet another position here in the FAA. I won't comment on whether or not it's a good idea to pursue a dispatch career, but as a pilot, it's always good to have more stuff to fall back on...