It's a waste of money if you're not in shape for it or you've got the wrong doubles partners. double bbbj, cowgirl and daty at the same time, k9 + 69, k9 with an ass in your face, switching back and forth, stacked pussies. Even just having one girl watch and cheer her friend on. Doubles can definitely be worth it.
I agree it can be a waste of time if you're really only there for one girl and one girl is doing all the work. I've had that experience too.