Cash purchases is instant and have the tendency to be final and irreversible, unless seller agreed otherwise.
Cash purchases for goods and services that priced such as $4.64 could be troublesome, as changes could be given wrong and customers were unnoticed, and it is hard to manage and organise all the coins and makes it less obvious than other forms of payment (e.g. online payment system)
Cash can be forged, merchants without proper tool in aid could have a difficult time finding out,