Plug in solar doesn't make your house resilient to grid failures either. You would need an inverter that can generate an AC output without having an existing one to follow; a disconnect to isolate you from the grid during an outage, batteries to smooth the output, an electrician to install it, and an inspection to certify that it was all done correctly.
If you are going through all of that, there is not much benefit to plug-in solar instead of traditional.
Most of the balcony solar packages already include what you need. They include a battery and on that battery is a receptacle that will supply power if there is no mains. The dogtail that you insert into your house outlet only supplies power if there is mains, but the receptacle on the battery supplies power regardless.
So when the power goes out you unplug your fridge from the wall and plug it into the battery. In essence it operates like the standard camping battery/"solar generator", a la Jackery et al.
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.
What’s the cost of these half baked solutions? My cursory search shows about half of that or more.
You can go as far down the rabbit hole as you want. Most people don't have anything critical that needs to have power 100% of the time, a few hours without power won't hurt your fridge. The odds that the power goes out for long while you are on vacation is low enough that you can ignore it - besides most people tend to have less in their fridge when they go on vacation.
Where on the risk spectrum do you fall? I have a battery backup sump pump because I learned the hard way what happens when the power goes out and the generator doesn't start. If I fixed my generator though I'd have an automatic system that would run my sump pump, furnace, fridge, well, water heater, lights, computers, range, - and lots of other useful things as well so long as I'm careful about I run at the same time (anyone know how to fix a 1970s generator?)