Draco, aka Corbin:
"Why not take the clipings and bind them together and root all at ounce?"
Simply, because some of the cutting may not strike, and you will have to end up undoing the binding and doing it over again.
I've had a few goes at this with mixed results. I've found that supertight binding all the way around encourages rot and some of the cuttings will perish, again requiring a do-over.
Here are some of my successes and failures (with links to other members' projects also):
First attempt
Failed attempt
Do-over
pootsie