Yeti Ice is different to regular ice. It's designed to extend the life of regular ice by melting earlier and making the ice around it colder as it melts. It'll extend ice in your cooler by 0.5-1.5 days. People also use them as standalone ice packs.
An ice pack that weighs 4 pounds will stay cold longer than one that weighs 2 pounds. A 5-pound ice pack used inside a quality cooler can stay cold for up to two days. Since they're thicker, hard-sided blocks also stay cold significantly longer than soft ice packs.