I buy plenty of extra chips. Not as an investment, but as future traders down the line. But I can tell you value don't increase much. I have more chips than I care to own from Vacation Village, Speedway, New Frontier and others.
I lucked out at Key Largo. Ran out with roulettes and a few 25 and 5 dollar chips. My next tip was canceled and then they closed. Got a good price for them.
Barry