Their value as a chip is stated on each individual chip itself, but their value in terms of collection and auction are, so far, limited. Sites like eBay list several sales of these collector coins, with the prices ranging between a few dollars up to over $100 for the bigger sets.
As with most collector pieces, they become more valuable over time. Less than 20 years is considered recent enough not to be of any special value, but waiting a further 20 having purchased these coins will see their value more than recouped.
Chip collecting is similar to coin collecting. It is the deliberate act of taking chips from a casino for the purpose of collection, trading or selling. It used to be just for souvenir purposes, but with the introduction and massive growth of the internet it quickly became easier to buy, sell, trade and compare - making the hobby much more attractive and exciting to collecting fanatics.