I didn't really see the benefit to a shield until recently. The mods I'm most likely to drip have nice juice wells and I don't carry them in my pockets or lay them down.
But, then I picked up a couple of shields in advance of getting my VVPV. I knew from what a couple of the beta testers had said that I would appreciate having one for that mod. - Before my VVPV came, I ended up trying out the drip shields on a couple of tube mods that don't have drip wells and that I normally would use cartos on instead of dripping. It kept them perfectly clean. And, I suppose it does change the airflow somewhat.
Now, I find my drip shields to be an important accessory. One is always on my VVPV, of course, and the other seems to have found a home on one of my rough stacks.