Yet TradeMe still exists and people use direct bank transfers than any other payment method on the site. If your claim (that business this way is not practical) was true then people would not use direct bank transfers. But they do. Ipso facto your claim can't be true.
My claim was and still is that using cash eliminates many of the scams - your claim was that scamming was too infrequent to matter. I provided evidence that it was frequent enough that the marketplace warned you against handing over money via bank transfers (other than their own special bank transfer that still had no guarantees). Please read those links I posted - they actually specifically warn against bank transfers.
Again, the system is widely used here. So the onus is on you to back up your claim that it can't possibly work with evidence.
I refer you to the trademe trust and safety blog (yes, it really is called that): http://www.trademe.co.nz/trust...
But the system still works. You haven't provided any evidence that it doesn't. You haven't even provided evidence that the incidence of fraud is higher with direct bank transfers.
I don't need to provide evidence that it doesn't work because I never made the claim that it does not work. I claimed that untrusted transactions are best with payment and possession taking place at the same time, hence cash works best for this. The sites you pointed me to warn specifically about doing bank transfers.