It doesnt look like a scam to me. A carefull look at the documentation pa website you will notice that the vendors get money out of this as opposed to the ordinary vendor. Chero joining fee yacho 10-40 bucks is nothing to write home about. The vendors themselves are self employed business people and business has risk (maximum loss 10-40 kana ndiwevo). Competition is good for the market and this shows how far zim has come.
It might not work at all but it shows the bright future Zim has and the chutspah people have in innovation. More ideas guys in every industry