I have a similar set I inherited with an additional groove running down the centre of one jaw. I've always used them changing tips on the MIG welder, never for much else as I haven't found what they work well for. I'm not sure why my grandfather had them, he was a linesman in the signal corps but worked an office job after the war.
EDIT found the answer
The pair I have has sidecutters. The groove was to slide wire through between the handles and the wire could be clamped in the v-groove for pulling without damaging the wire.