Not only no standby loss but no pilot loss and no thermal loss on pipe
to tank. My small Bosch is 2 D cell battery ignition, no pilot.
Effecienceis of tankless are 81 - 94%, 94% for the new Takaki. Tanks
calcify on the bottom with scale. I recently removed a tank in my apt
building on relativly soft water. There was 14" of scale in the tank,
now that kills efficiency. Tankless dont loose efficiency as tanks do.
There are many sites showing individual units efficiencies. Overall
going from electric tank to Ng tankless my bills are down 75%.