The functional advantage is indeed limited, but I can tell you why I've done it: the twist uses up a couple mm of extra spoke. If you have a hub and a rim and a pile of spokes of the wrong length and it's not worth it to you to go buy spokes of the right length, then the twisted spoke thing may work out for you. For a little while.

For example, I built a 20 wheel with a three speed hub for my daughter. I knew she would ride it only during the summer, and only for one or two summers before she outgrew it. She wasn't sure she'd like it, and I was under strict instructions to not spend money on this project.

It was a success. The wheel held up fine. She rode it a lot. She has now outgrown it.

Wheels like this tend to not last very long, because it is very difficult to get the same spoke tension above the twist as below it. So they tend to fatigue at the hub, and when they start to break, the wheel is done.