Why assignments contracts?

[Jacquelyn Sarpong]

Just playing curious. Why assignments contracts? I know it protects the wholesaler. But why not do two joint ventures contacts with both the seller and the buyer.  And get paid on the back end by the buyer.  That way,  no money upfront and the seller don't freak out when he sees his much your getting.  The buyer has to pay you anyway.  Any input is welcome.