Shame a 5v "fake" PPS voltage couldn't somehow be obtained or patched in. Loads of chargers would work then.
My pocket PD can request 5v5a from quite a few chargers in PPS mode.
My pocket PD can request 5v5a from quite a few chargers in PPS mode.
With that said, DisplayPort Alternate Mode would be considerably more straightforward.
There is real cost savings here -- the RPi5 avoided the need for a buck circuit, and for that matter probably a dedicated PD controller chip.
In contrast, in the context of a "cheap vape pen" you have a battery which means you need to be able to convert to (and from!) battery voltage, so you need that conversion circuitry anyway.