[McGruff]

We kept our old AT&T land line with a non powered phone for power outage use. Come to find out the phone didn’t work during a power outage because the sub-station lost power. Apparently it uses digital switching now or something. Thinking about doing the same you are.

[Baseballguy]

Being in the telephone business there are few true POTS service. Most are running a softswitch which are internet based.
The only issue if you loose power is not to try and charge your cell phone, This always drains your phone. Dont try to live by the internet unless you dont care about regional power outages. Another tidbit is even your internet is based on phone switches and telephone company's ability to have power. Most cell tower are self powered.
For babby sitters, have a child phone they are very cheap and are not smart phones. The child phone then can be turned over to your kid when they get to pre-school.

[djf]

A few years back, there was a pretty bad ice storm here that knocked out the power for almost 3 days.
My cell continued to work.
My land line continued to work.

About 8 hours after the power went out, my land line ceased. I think the substation I’m connected through ran out of AUX power then.