The hole is a form of cancellation. Casinos cancel chips in quite a few ways but this happens to be my least favorite....

The affect on value depends on the chip but generally a cancelled chip will be worth 10% - 25% of what it would be worth uncancelled. Again, it depends on the chip, its rarity in both forms, demand, etc.

This chip in uncancelled condition would be worth A LOT. According to Mr. Spragg's guide, it would be Z7. According to his guide, the book value is $8,000+. In cancelled condition, it lists at $250. Of course, in this market/economy book value or even 1/2 of book value can be difficult to achieve.