There's a comment along those lines in the Google SRE book iirc; author was saying why should it matter to have some kind of service with 5 nines if the user's

There's a comment along those lines in the Google SRE book iirc; author was saying why should it matter to have some kind of service with 5 nines if the user's condition (flaky WiFi, laptop rebooting etc) had a way worse availability