Physically unsafe? Security unsafe? And 'use' in what sense? Day to day main device with security credentials, financial/banking apps, etc? Connecting to co

Physically unsafe? Security unsafe? And 'use' in what sense? Day to day main device with security credentials, financial/banking apps, etc? Connecting to corporate/VPN resources? For professional and important personal use, I probably wouldn't use anything not 'officially supported'. When my banking apps won't install/update, that's probably the time. But I just re-used an old wiped iphone 5s a few weeks ago to browse some news sites. No issues, other than it felt less snappy than current devices. But it's not tied to any other part of my life at this point (apple id, bank, medical, etc).