The vail covers your face, which is the #2 most giving away sign, right after movement. The whole trick is that you can see though it, but no one can see your face. It's more like a really effective face camouflage than a silhouette-breaking kind of stuff.
So it's not comparable to a ghillie hood (and honestly, claiming the veil will get caught in branches and then recommending a ghillie is pretty bogus to say at least)
You could use it to somewhat cover your whole body and even some of your gun when needed, but unless you have plenty of branches and such between you and your target, the resulting green blob is not natural at all, and easily identifiable for someone actively looking for a sniper. Some veils have camouflage patterns applied, and that helps too, but still far from and effective standalone camouflage solution.
Just use it around your neck, apply it over your face when needed, and complement it with some silhouette breaking stuff. A Viper Hood kind of setup with local vegetation would be my #1 choice.
I would only consider it as my primary camouflage mean when mission demands a really lightweight, fresh and high speed kind of setup.