Depends on the brand. I'd argue that comforters are more expensive. Most comforters are $60 and up for one blanket.

Whereas you can get 34 pounds of moving blankets for $66

https://www.amazon.com/Sure-Max-Packing-Moving-Blankets-Furniture/dp/B07KMC8YYV/ref=sr_1_26?

There's tons and tons of people who have spectacular audio using moving blankets and PVC booth, including people who are on Disney right now. I wouldn't say moving blankets are 'bad advice'. It's a fantastic setup, but you do need to layer it correctly.