At least on an iPhone, erased is erased. On android some versions use full disk encryption but many do not, it's a guess.
Please don't hijack an important security discussion to engage in meaningless platform flamage. Users with Android phones have this available and they should enable it, not be told that they need to "guess".
Also the parent post was talking about usage, not availability of encryption. So while recent Android versions most certainly offer encryption, it might not be enabled. iOS encrypted by default, as it should be.