Every day people go to work and turn off their electrical devices. Switching your home to off-grid solar + batteries is just like going to work and not coming back. The grid can handle it.

If many houses install off-grid solar, it's still not going to have a negative effect on the grid because the change is spread out over time.

It does mean that less generating capacity is needed over the long term, but decision makers can just get that data directly from the grid. I don't see what extra information the permit is adding.