Id say for discounts is the only reason why they would choose to do so.
Yes they will use for discounts and also because the transactions made with bitcoins are irreversible.
Perhaps it is for cheaters would be important to interrupt the transaction after remittances, but if it is a serious matter, no one is capable of such problems will not be. Why all this do not understand. Although if you are faced with such a problem, then yes, I understand, but otherwise I do not know whether it makes sense.