He slid one to the dealer and it was witnessed by the tourney organizers, the casino and the dude from the Swiss bank. It's a piece of plastic that represents a dollar amount. You couldn't take a chip to McDonald's and use it as legal tender. Everyone's like 'zomg chips don't actually have worth outside of the tournament so he actually gave the dealer nothing!' Well technically they don't really have worth inside the tournament either, they're just a representation of your place in the game. You know how you know that's probably the case? Because the other explanation makes zero fucking sense haha.
I always just assumed the 500k was deducted from his winnings. The chip is just representative of Bond's intent to tip. That part isn't hard to understand - although you wouldn't know it by the responses in this thread lol - but I don't think that was the point of the chip slide.