It's finally happening to me. Verizon just sent me a letter stating they are going to replace my copper landline service with fiber optics. They are "upgrading" my service.
As part of my "upgrade" they will install a battery operated back up "device" in case of a power failure. Now of course what they won't tell you that "device" will only give you ONE hour of standby time, not talk time, just standby time. Presumably if you use your phone, that back up time will be considerably less. And of course, you need to supply the batteries, even though they state this service upgrade is of "no cost to you".
Now we very seldom loose power where I am. Last time that happened was in the general blackout of 2003, when the whole northeast lost power. That blackout lasted for 22 hours. Before that, it was 1977, that one lasted 20hrs, that last one in 1965 lasted 7 hours (Brooklyn).
And the phones NEVER failed. They had their own, back-up generators so we had service throughout the duration.
So now, thanks to this new "upgrade" I can look forward to loosing my phones shortly after a blackout.