That "something" is at least the entire userspace, so any attempt at doing so ends up being UX-equivalent to a full restart - while having a decent chance of leaving unintended trace data lying around in memory.
A full restart guarantees that everything will be wiped.
It’s not about data being wiped. It’s that neither Android nor iOS has
fully encrypted storage after you reboot and enter your credentials - biometric or passcodes.
A full restart guarantees that everything will be wiped.