The arcade machines withdrawing units is because they work in the same way as the ones in the casino in that they require units to play.
The tokens merely work as a a sort of limiter to stop people from hogging the arcade machines 24/7 by requiring you to have “bought” tokens in order to play.
The act of buying the tokens from the token machine is sort of a pseudo transaction that doesn’t actually take any units.
When you interact with the machine the amount of tokens you’re carrying is reduced bringing you closer to the point where you gotta “buy” more tokens then when the game is over a certain amount of units are withdrawn from your balance.
The transaction box isn’t supposed up when it withdraws the units at the end of the game, that is a visual bug.
I am however not sure why they decided to make it look like the units are withdrawn when you buy tokens, im guessing it’s to make it feel like a real life arcade where you would also pay for tokens.