OM-D, HLD-6 and 2 battery advantage???

Is there an advantage to using 2 batteries - 1 in the camera and 1 in the HLD-6?

Or should you just keep changing the battery in the HLD-6 when needing to be replaced with a fully charged one?

With the E-3 it was not decision as camera with HLD-4 required 2 batteries and no other options.

Gary

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