My theory is that KRT are used for retail daily transaction, eg buying grocery using CHAI payment app. UST is used on many protocols on Terra ecosystem such as Anchor Protocol.

Now let's see the volume of transaction of KRT vs UST. UST has much bigger volume compared to KRT but KRT has much higher transaction count than UST.

First let's see how many addresses are holding at least 10USD value in their wallet. As of today, from graph below, we have 728,239 addresses holding KRT and 31,082 addresses holding UST.