I've read that they have to be reachable in order to get any kind of state benefits, and being unreachable leads to automatic disqualification - which is a big problem as homeless people often lose their phones or have them stolen.

As far as smartphones being a necessity goes, I have never owned a smartphone myself, and do not carry any phone at all most of the time. I have just gone on living like I did before smartphones, though I am aware that I am locked out of more and more things. I am beginning to resent things like parking that requires a smartphone. I don't understand the lack of back up options.

Rather than insisting on 'smartphones as a human right', I'd rather see 'opting out' as a human right.