I would argue that using a bigger chip has a positive impact on privacy, in some situations.

If you spend two chips of equal value, someone looking would know that you sent the chip value to CM on or before each chip was created. With a single, larger chip, someone looking would know you sent the chip value on or before the date the larger chip was created.

If someone knows all transactions going to CM, the list of transactions that meet the criteria of using two small chips is going to be smaller than using a single, larger chip.