Each to his own, as my grandmother often said*. With higher proof spirits, I enjoy both a bit of dilution and a cooler than room temp. My ice cube trays make ~ 1 oz cubes. Every now and then, I make a tray of 1/4 oz slivers to use for this purpose. I store them in a zip top with the big clear 2-inch cubes I use in some cocktails. I add one to a 2 oz pour and am usually happy with that. Maybe I should compare that to adding room temp water? Or maybe I should just have another 🙃
* another thing she used to say was, “When I go, put a bottle at me head and another at me feet so I’ll have enough 'til I get there.” No mention of ice nor water!