I have been playing roulette, on a busy table, and whilst playing decided to use a promo/ncv/voucher, call it what you will.
Several times a suit has told the dealer that because I already have color on the table, he should switch out the promo for my color.

Those NCL promo chips did not pay off at half value, they paid at full value, and the paper tickets were switched out to cash chips prior to the spin.