The problem I have with launching unhooked is its easier to get out of control for people who don't know what they are doing. I.e. trying to hook back in alone can be a good way for things to go pear shaped.
I agree, just a week ago I saw a guy mess up his tethered launch, don't know exactly what happened cause I was far away but did see the kite end up smashing into the dunes. What I do know is this guy was an inexperienced kiter and shouldn't attempt self-launching...
Regardless of your method, self-launching is only safer for advanced kiter only who can systematically take the right actions to help minimize the risk and do the right thing fast if things go bad.