eBay and Craigslist finds

I can't see why someone would make those other than for asthetics (which are very good I admit), but i'm sure they'll try to promote them as letting you put more power down or something.

That's what I mean; if they were intended for that, surely the crank arm would absorb a great deal of your pedal stroke's power, meaning the design is just failing epically in terms of it's purpose?