It's a good idea, but it's not new at all. I recall a Tom Brown book mentioning the same idea something like 20 years ag. He just tacked two shirts together and left the top seam open for stuffing.

At $99, I say forget it. I'll go to the Sally Ann, pick up a $5 vest and dump out the stuffing. I can stuff this "windbreaker" with dry grass any time I want.