Clearly the key thing here is the security but I having used a backup to switch to a new phone recently, I was amazed at what an appallingly bad user experience

Clearly the key thing here is the security but I having used a backup to switch to a new phone recently, I was amazed at what an appallingly bad user experience it was - it got stuck multiple times (no fault of my own and no way to tell it to stop trying to hopelessly continue) and then you have to wait longer and longer each time to repeat it.