I am not sure how dangerous crown rust disease is to oat crops. I been looking into crown rust resistant oats because it is supposed to have a redox effect (most minerals are more bio-available to plants in a redox state than an oxidized state) on the soil. But the fungal disease evolves rather rapidly to new resistance.
Research suggests that for oat cultivars with race‐specific resistance, the resistance does not remain effective for more than about five years, because the crown rust population evolves to more readily infect and thrive on their host.
-https://alseed.com/oats-managing-crown-rust-and-targeting-fungicide-use/