One of the facilities I worked at shared a building with a coral farm (Bob M) which had a 40g fuge that was just a massive colony of valonia with sponges, tunicates and mini brittle stars. It was pretty dang impressive.
I had both purple and green bubble algae in my old tank. Probably will in my new tank.
I admit they did look rather nice in small amounts.
But an interesting problem with the purple is that as it ages and dies, it gets this ugly white color.