Quite a pretty way of making first reflection/absorption panels. As usual, likely better than nothing and much more effective than the typical foam stuff sold. But, have you ever looked at the cost of quality towels?
Likely fine for the home broadcaster for sure. If you going to actually build panels for this, seems to me using safe n sound or rockwool would be better choice. Or wrap proven materials in the frame with a pretty printed towel? Or any breathable cloth...
This video is obviously not for those that plan to record drums or mix records with audio monitors, so that is irrelevant to discuss other than making sure one does not think that this is the fix for everything. That being said, I have had crappy acoustic guitar recordings without room treatment. My rooms now have much better rockwool acoustic treatment as well as bass traps. It does make a huge difference for acoustic instruments as well as vocals, because the room is a big part of what is being recorded. If the room sounds like shit, a condenser mic will tell you.
By the way, not all bath towels are the same. The cheap ass half + nylon ones that don't absorb water when you get out of the shower, are also not as effective for sound absorption. Those are the ones I usually in thrift stores or free in crappy beach hotels. The 100% cotton ones that are $40 a towel are awesome! LOL