True. My Blizzcon acquired physical authenticator started alerting me to a Low Battery condition two years ago.
The easy solution would be to put the app onto my smart phone but I do not have one of my own. As an employee benefit, I have always had a fully functional smartphone - but for security reasons, the research institute I work for only permits us to add apps if they are pre-approved by IT. Gaming (or gambling) apps are specifically prohibited so I’ve been using the physical auth as long as possible.
In fact anticipating an eventual low battery issue, I’ve kept a second unregistered physical auth in the fridge to preserve it - only to find that these days - Blizz will not allow anyone to replace an old physical auth with a preserved one.
So two years ago I bought a Pay As You Go (no contract) cell phone just for Warcraft only to find that these prepaid numbers were rejected by Blizzard for the purpose of authorizing play. I gather there is something different about numbers from prepaid plans - they are “virtual” or something. Don’t know the details and couldn’t fix it so I returned the prepaid phone.
I did find a solution though… MobileSMS.io. They are a phone number rental service that uses real sim card numbers that are NOT prepaid. If you Google them up and check it out you’ll see they offer a variety of temporary phone numbers to choose from, including one-time use, 7 day rental, 30 day rental, and long term rental numbers.
So I used the rented phone number - entering the verification code sent to the temporary phone number provided by MobileSMS.io filling out all the details on the Battle.net account page, including the temporary phone number provided by MobileSMS.io.
I played that way for quite some time and all was well.
But while this was going on, a bunch of us who work there (almost 100 employees including some top researchers) signed a petition to our IT department asking they take another look at the Blizzard phone authenticator app, and a couple of months ago they added it to the approved list - so I canceled my cheap MobileSMS.io rental - ultimately adding the Blizz app to my work phone (like a normal person).
As a great little bonus I now understand that a bunch of people I work with also play Blizz games - which is fun because I never knew that. Some of us have even started playing together - despite all being on different servers and factions.
But the bottom line is if you do not have a phone or just do not want to give Blizz your real phone number, you can do as I did for a while and rent one from a company like MobileSMS.io