I'll have you know that I read all of my posts out loud several times before submitting them. Otherwise I wouldn't be sure if they were up to HN's high standards.
Having not read UBIK, I'm not sure what exactly you were going for by comparing having to keep your phone charged to "a deeply unsettling existential horror story, a nightmare you'll never be sure you've woken up from"[0].
I genuinely do not see how being required to manage a phone's battery is any more onerous a requirement to place on someone than keeping track of a key. People are used to doing both already, and of course I'm not suggesting that it would be acceptable to remove existing fallback measure like resetting locks in the event of a lost key/phone.
[0]: Grossman, Lev. "Ubik–All-Time 100 Novels". Time. (via Wikipedia)