Deep Nymphing. I use it big time, but the bobber/indicator is used more for suspension.
I use a styro ball from the size of a dime to the size of quarter depending on water and fish size. It is doing the same thing as that Chernobyl ant or the Hopper is doing without the added hook on the surface.
Which is nice in a two hook state and the fish are deep and NOT on the surface.
I have been doing this for many years. Phil Rowely and Brian Chan both use the same indictors I use.
One fly I found AWESOME for Bluegill is a bead head softhackle with a bright pink tag.
Another one is one I received in a Carp fly swap here.
I have a video of Sir Oliver Ewards. Very old school. Used Nymphs made from mohair bought in sewing supply stores. Weights them heavily with thick wire. But hwe shows his line. A leader with RED thread wrapped heavily at the loop to line. He said this is his indicator. So, even old school uses them.
Maybe if they are super small, they are more acceptable, I don't know. Maybe if it is a giant fly that doesn't match anything on earth, they are acceptable..I don't know.
But I do use them and I catch fish ;-)