I suspect that if you drop an acceptable bait in front of their noses, they'll take it. Maybe they'll be more likely to see it if it has some bling, but how do you measure that effect? Well, you can't. You can have faith, as in believing in God or the tooth fairy. Either you believe or you don't, and trying to convince anyone of your view is not a good idea.
I often use bling—just in case
. Sometimes I don't. Below are two gurnard caught at Port Waikato on blingless traces made with black mono. The bait was salted bonito (with apologies to Chad). That's a single 8/0 hook you see, but they don't all hook so well.
Next one down shows James Benge's bling. I took this shot at Ocean Beach. As I recall, James caught the only gurnard that night
. Even Chad dipped out—no shit
. Did James's bling do the business? Who knows. We can say it didn't scare them off.