I think SoJ is meant for people to be able to use some of the elemental affixes that are on weapons that are locked but not be handcuffed to a certain skill rune.
Like WkL for monks. Or if we wanted to use a fire rune but still use doombringer or azure wrath.
Really seems to me like a QoL for early to mid level gearing. Or a VERY high paragon when you can drop a survivability item to eek out a tad more damage.