I think it's fair to say that you essentially need text messages (in the US). However, I question if you need a smartphone beyond that--although a working individual may. I don't need to do any of the things you list with a smartphone although e.g. COVID vax status may in some places. (Just a piece of paper has been sufficient whenever I've needed to.)

I don't really disagree that we're moving to a place where a smartphone is universally needed because of apps but I'm not sure we're universally there today.

I think “need” might be too absolutist of a term. But yeah, not having a device connected to the internet (which is what we’re talking about here, not a supplemental device to your MacBook or whatever) makes life a lot harder.

So no, it’s not food and water level necessary but it’s pretty damn important.

Need a smartphone? Maybe not. Need an internet connection? Probably.

A smartphone just happens to be the easiest way to get phone/SMS & internet. As noted elsewhere, a massive number of Americans (and people worldwide) use their phone as their only means of internet access.

> Just a piece of paper has been sufficient whenever I've needed to

OK so you need a printer, ink, probably a PC… (Or at least access to one, which would be a fine requirement, if the US had good public transport and libraries...)

I don't think I buy that argument very much, though. You can do all of those things in the same way you would have done them before the advent of smartphones - snail mail (or use a library/personal computer to check emails), visit a bank in branch, send text messages to friends on a flip phone. Heck, even most vaccination systems I've seen worldwide have the option of a printed QR code proof.

I won't disagree that these things are massively inconvenient compared to doing it all though a smartphone, but it's far from impossible.