difference of PW vs other battries
My 2p-worth (no experience of anything other than PW)
We have UPS on critical IT gear/CCTV
My individual-PC type UPSs seem to fail more frequently than we have actual powercuts
That doesn't apply to more decent kit - we don't have any problem with the UPS which protects the server room at work (knock-on-wood). So I'm happy to have PowerWall Gateway ... it isn't guaranteed to switch over in time in all instances (forgotten what its weakpoint is - brownout that then leads to a powercut (albeit only for a second or so) - something along those lines).
But even my nearly-knackered UPSs will provide me with a second or two of power, and the capacitors in PCs etc. may well survive a very short powercut ... but even going round fixing all the electric clocks in the house is an inconvenience. Oven won't come on at all until "a time" is set, so its time is never right 'coz no one could be bothered to reset it probably after a powercut when all they wanted was "Turn on darn infernal machine", and after that no one can remember the secret combination of buttons presses to enable resetting it. Poxy UI design.
I work from home and Accountant has put some portion of PowerWall and PV through as business expense (no recollection, might have been anything from 0%-100% for all I can remember)
I am installing an emergency circuit which I can manually switch to in the event of a power outage
Had the whole house rewired a few years ago. Wish they had suggested to me that I might organise "critical circuits" ...
... even with a PowerWall when we get a powercut its either a couple of seconds, or a JCB has gone through a cable and its going to be "some hours". Or its a scheduled powercut probably 9AM - 4PM or maybe lights have gone out during a big storm and probably going to be off for "plenty of hours"
In all bar the "couple of seconds" powercut I would be happy to turn off the non-essential circuits, to maximise PowerWall run time. On the couple of occasions when that has happened I've had to do that manually guessing which circuits we can do without, and that I won't be accidentally turning off a PC with untold hours of unsaved work on it! or the sewage digester thingie
But having the PowerWall run the whole house means that I have "options" in that regard.
(checking APP : 7 powercuts this year, 18 last year ... all "a few seconds" except for one 5 hours and one 8 hours (scheduled for trimming-trees, and one of the big winter storms)