> If I’m gone on a trip for 2 weeks my hot water bill is zero

You mention other advantages, but money isn't one. You're limited to 100% efficiency with tankless.

Although an idle hot water tank can waste ~70W (~1.7kWh) of power, this is way more than made up for by using a heat pump. Plus tankless strains the grid a lot more than any system with a buffer built in.