I vote for; not create smaller chips, for now, 1mBTC equal to $10 is still convenient.
Unless bitcoin price reaches $15,000 or $20,000 then some people may want to mix smaller chips, like 0.5mBTC.
Like mentioned above; if there are big demands from customers to introduce smaller chips, then there you go.
It probably will not be very long before Bitcoin does reach that price. I would think introducing smaller chips is a sensible thing to do. If there is isn't much demand for them yet it will soon come and I cannot see any problem it would create.
Edit:
A question; when people withdraw, sweep the private keys, the fees to be paid automatically based on the normal fees preferred by blockchain or Chipmixer can set it to lower or higher fees if customers ask to?
ChipMixer gives you the private keys so you are fully in control of how you spend your coins and what fees you pay. For example, you could make a new Electrum wallet with the "Import Bitcoin address or private keys" option and then send a transaction with a manually selected fee.