To gp’s point, if you’re going through it all just implement it at your panel/subpanel. Mine does auto switch over to power the entire panel and I only know about it from an app notification. Then I can decide if and where I want to power down usage in the house to conserve battery.

Having to plug in individual appliances seems to defeat the entire purpose. What happens if you’re away on holiday? Come home to a fridge full of trash? If power is back, do you even know how long the outage lasted? What about other devices that generally should have nonstop power or are typically hardwired? Sump pumps, HVAC equipment, water heaters, etc.

Spending $3000 to add auto-switch to a $500 battery is not something most people are going to do.