User blog comment:ClariS/Noria, The Mystical Diviner/@comment-60764-20120314115946/@comment-4881935-20120314150020

Well, the heal on her E is just there so the user will not obligated to engage in a fight right after escaping a fight (see the anti-pattern). Hence, if you just retreat, she will benefit from the heal. If she fights, the shield. The shield length is average when compare with other shield. The heal is not it's important part of her spell though.