clutch fan vs standard fan

I use sort of a compromise to the "no-fan-at-all" approach on my Duster with a very small all-plastic flex fan. I doubt if it weighs more than 10oz., so drag is minimal. With a bit over two inches from the blade tips to the shroud, it pulls just enough air at idle to smooth out the temp spike to prevent overheating if I get stopped in traffic on a hot day. It couldn't possibly do much damage if it ever came apart (doubtful) - it is one solid piece of platic or polymer composite of some sort.