Those might help tame some high end reflections, but they won't trap any bass which is what most rooms really need most. That's where GIK traps rule!
Inexpensive Cork Room Treatments
Had a happy discovery this week that inexpensive, egg-carton-waffled cork bath mats make great room treatments. They're 24" x 18" or 36" x 24", and the price of a couple of CDs. My wife bought an extra one, and I stole it to treat the wall behind and between my speakers with the result of a more focused center image and no hardness in the treble at volumes that previously over-energized my plaster walls. They'd be good at first-reflection points, too. Since they're a natural material, they don't look too bad either.