I find them to be the only way to push shield strength up to a number that I'm happy with. On shield tanking builds, they're indispensable.
Alternatively, if they detect Guardian tech, there's a chance they'll think I'm one of them and toddle off. Or better yet, maybe I can sail along with them like a person covered in zombie guts wandering around with a pack of zombies who don't notice that they're there.
And yes, I did get this idea from The Walking Dead thank you very much.