An alternative would be a supercapacitor and a voltage divider connected to the ADC pin of the microcontroller. When the 5V rail dies, the supercapacitor can hold 3.3V for a few seconds while you write everything to the EEPROM.
(Hey Dang. Can we get a ban button? There's a few people here that are impossible to conduct rational discourse with. My sanity would improve if they were simply gone from my view.)
Use this as you like.
Please stop fucking with people in this way. It's callous, unnecessary, and antithetical to the greater good. We don't come here to get accused of things.
(edit: Today, I learned about the existence of a chip that does a clever thing. That made me curious: After all, I've been passively wondering for -decades- about how electronic things remember their previous state without power, and without hammering an EEPROM.
I could have learned more about this at any time over the years, but I just never bothered with doing so.
And today, it was right in front of my face -- with a part number! That gave me a very easy place to start, so I started.
I read up on it a bit using the datasheet and a whitepaper. I learned some about how it does that clever thing, and I wrote a few sentences about this new-to-me stuff in a way that I felt would be approachable and appreciated by this particular audience.
That's what we're here for -- to be curious, to share ideas, and to learn stuff from others. Not for fucking with people.)
An extra UI element or two should be enough. Maybe with sticky options for collapse-by-default or hide-by-default at the top of each HN comment section.
And the list of usernames can be stored and edited in the purveyor's HN bio (in plain text, like a monster), so that it works automatically across devices.