You get bonus stats increase from using same attribute eidolons as your soul. You'll eventually want 6 SSR Eidolons of your team's element as a goal, which is a minor thing to worry about right now. Also having the effect on even longer is a nice addition.
Jorm works great as a stat stick since she's easy to acquire, unlike previous eidolons, you can have 2 (10+ copies) fully limit break copies of her if you put in enough effort, compared to previous event where you are lucky if you even got 2 or 3 of 4 limit breaks off of a single copy, giving Jorm higher stats meaning more beneficial use.