Normally, there are plugs labeled for critical equipment (as in, they’re connected to the generators even if the power goes out). But yeah, everything non-essential is kinda down.
You still absolutely need to go check your equipment during a power outage, and make sure your “critical” stuff is plugged into the “generator outlets”. There’s battery power on (pretty much) all critical equipment, so you have a buffer.
I personally don’t rely on batteries being my backup, and keep my critical stuff plugged into the labeled outlets… but you still gotta check; and deal with power being out for everything else