The question, of course, was not for me, but since I also own a V6400 and also experience daily blackouts, as an example I can tell you that this is happening in Ukraine. F*cking russians destroyed almost all heat and hydroelectric power plants in my country with missiles, only nuclear power and a little bit of solar power is left, but they are not enough, so at some days we live up to 18-20 hours without light, even in the capital. In this situation V6400 is a real savior, which manages to charge in 2-3 hours while there is electricity, and then supply electricity to the apartment for next 7 hours while there is no power. To survive the winter, it would be ideal to have an additional battery, but unfortunately for the V6400 version they are not available in my country yet.
Peace be with you all.