Place ice water bowl somewhere and leave the other options unchanged, so your cat is never in a position where they have to choose between ice water and no water.
Ice water can constrict blood vessels and lead to slower digestion if consumed in large quantities. However, the chances of this occurring in cats are pretty low.
Ice water is a great way to add variety to your cat’s routine and potentially encourage them to drink water. Both of these are good things in moderation.