I guess you would have to classify it a TITO (Ticket In Ticket Out)
But technically it never comes out, so it should just be called a TI (Ticket In).

However, if you think about it, a TITO should really be called a TOTI (Ticket Out Ticket In) because it comes out first, then goes in.

Of course you can call it a coupon too.

But is's all academic because nobody is going to collect those because it is worth $5 cash as is, and once used it disappears into the slot machine.