"More efficient" is not a binary thing. Taking an efficient engine that's capable of throwing two tons of steel down a highway at 100 mph and using it to charge a lithium ion battery is like killing an ant with a sledgehammer.

An F150 consumes ~2 litres of fuel an hour at idle and provides 400 watts of power through its outlet. A Bosch leaf blower is 2400 watt. Petrol powered leaf blowers do not use 12 liters of fuel an hour.

Sure, the emissions in some ways will be lower, but it's not an unambiguous gain and it's not anything close to an environmentally friendly way to run a leaf blower.

This is clearly a niche for PHEVs or BEVs.