> 2. People don't have their phone on them all the time (and some don't even have a smartphone). Even if people have their phones all the time there's always a

> 2. People don't have their phone on them all the time (and some don't even have a smartphone). Even if people have their phones all the time there's always a possibility that components on the device might suddenly fail. The charging port in my iPhone stopped working on one May morning and thus device died. I temporarily lost access to most of the apps incl. 2FA code generators for about a month. Luckily one of service centers was able to find component and replace it cheaply.