Don't know if it's been said yet but:
There is no way to standardize the unhooked launch to all kites and conditions. Also all brands are acting different when unhooked.
Small kites are easier to control unhooked, that's why some ride them with a pulley bar. Same as unhooked.
Launching unhooked to be safe? not sure about that. If your kite, like most new hybrids and bows, flies with the front lines, you need to be hooked in, or at least fully depower the kite. Still not safe with bigger kites i.m.o.
It's easier to just let go for sure, but if you are smart enough you set up the kite correctly, chose the right size for the conditions and launch from a safe spot, you don't have to let go.
Imagine to launch the wrong kite, thinking it's the right size, unhooked and a stronger gust hit you! Just let go? sure, if you are all alone in the middle of nowhere.
Do that , let's say Kailua with 100+ people on the beach, you get your ass kicked off the beach (if you are lucky) (ps: by you, I mean: who ever)