as the others have already stated, but i'll simplify:

Pai Gow Whenever I go to get 0.25 chips, I go to the pai gow tables.

Craps-on low table minimum (below $5.00), which is getting much more scarce.

CA Card Rooms that require a per hand fee.

Ive also seen them used at BJ tables a couple of times, but I dont remember where. It doesnt make much sense to me to use 0.25 chips because of the cost to produce them. At least with the 0.50 chips, they dont lose money on the chips.