My field experience says that suspenders are there to hold everything in place, more or less. During hard physical activity outdoors, I've always had a problem keeping my shirt tucked into my pants and my pants up high enough that the crotch didn't interfere with my stretch and stride. A belt is great for gp, but when bucking timber, or chasing elk, or hiking the fjords, suspenders really made a big difference in ease of motion and in keeping the ensemble together. There were occasions where, without the benefit of suspenders, I would charge up a hill, choker in hand, ending up at the top looking like Dick Van Dyke dancing with the Penguins in Mary Poppins. Lowriders may be the "In" style for gangstas and hooligans in metro center, but they are dysfunctional in the wild. I dunno about the air flow part, that's never been a concern for me or anyone I've spent time with out in the boonies. Keeping them britches up over my hip bones has been the prime (and only) consideration for me using them.