standby tank heat lost isnt wasted enegy in tthe winter since it helps
heat your home.

only in the summer is it wasted and since the entire building is warmer
the loss is less.

a 120 degree heater sitting in a 40 degree home looses lots more
standby heat than the same 120 degree heater sitting in a 80 degree
basement

there are super high gas condensing hot water tanks that elminate the
standing pilot and are fan vented like 90+ furnaces these 98% efficent
hot water tanks are a good solution. Pelonis is one brand

at very low flows a tankless may not trip on leaving you with cold
water for say a sink.