Yeah but just cuz you take your 5% cdr from masteries doesn't mean you can afford or would want to get cdr boots. A lost 5% isn't a big deal really but like maokai for example it'd be nice to get 5% from masteries, 20% from frozen heart, and 15% from visage. Idk multiples of 5 honestly seem more intuitive for some tank items to me mainly because of the masteries.