I definately think so.
What is nice is you can put them around vocalists to tame room reverb and reflections, or acoustic guitar... I made some (not round) that I use, so that I end up recording most everything in the bigger romm and can tame the room from lively to nearly dead just by bringing more of the gobos close to the recording source.
I had a friend that made his own round ones by going to a commercial airconditioning supply house and getting the compressed fiberglass ducting. He stuffed the cavity inside with fiberglass and made wood plugs for the ends, covered them in fabric and mounted them on mic stands.