So an average lightning bolt is a gigajoule or so. These aren’t average lightning bolts. And OP’s comparison point of the energy used by a house in a day seems

So an average lightning bolt is a gigajoule or so. These aren’t average lightning bolts. And OP’s comparison point of the energy used by a house in a day seems arbitrary when we are talking about an event that lasts seconds. If your 30kWh number is reasonable for a house’s daily energy usage, in the 17 second duration of this record breaking lightning bolt a house uses about 21 kJ. So even if the bolt itself only moves that estimated 1gJ of energy, it’s enough electricity to power about 47000 homes for those 17 seconds. These are not ‘modest’ amounts of energy by any stretch.