In my experience as a VT homeowner we have relatively frequent short outages. It's pretty rural and the weather is brutal. I think the grid doesn't have as much redundancy as denser areas. We had one 3 day outage 2 years ago in the middle of winter which got quite dangerous, but otherwise I haven't had anything more than a few hours.
Also we have propane heat - but I need electricity for the blower and control board. So the electric consumption is pretty minimal, but it is critical.
I tried to signup for this program but the building code gets in the way. You need 3' from both edges of the battery to a window or door. I don't have a wall with 8-9' between windows. The alternative is to build a fire proof room in your house which takes up a lot of space. Ultimately it was not worth it even with all the financial incentives. The rules might seem innocuous but they're a dealbreaker. It's far easier to get a propane or diesel generator installed.
Generators are generally used outside. There are some rated for use inside, but they also have strict regulations on how that is done. (there are also some used inside but they will kill someone soon)
Maybe where you live, but where I live the temperature outside is bad for batteries.
Though what is "inside" is debatable. My car can sit outside because it has the batteries in a case that is climate controlled when needed, and so the batteries count as inside even though they are in a car that is outside.
I would be much more nervous about a 13+ kWh battery than a natural gas generator.
The generator is generally only risky when in operation. For natural gas units, a normally-closed solenoid keeps the gas off unless the controller actively commands it. A battery is constantly in a state of non zero fire risk when charged.
Also we have propane heat - but I need electricity for the blower and control board. So the electric consumption is pretty minimal, but it is critical.