4 days
These batteries aren’t designed or built for whole home backup, they can’t produce power when the grid is down (some have dedicated sockets for you to draw power from like a normal battery but they don’t back feed). All the scenarios you’re thinking of why these are bad are already accounted for.
You’re missing the point, the point is the batteries are designed specifically to NOT back feed into the grid.
Instead of telling people to re-read your posts, why don’t you actually go and read up on the very things you’re being critical of without the most basic understanding of how they actually work.