Elena was driven solely by the instinct to fix her mistakes and free Arwen of the entity seeking to usurp her place in reality.
For that reason, she was willing to go the extra mile, even if it meant igniting her very essence, drawing upon a power that brought her close to the threshold of a proxy.
Of course, she didn't know what a proxy actually meant and only did it intending to grow her capabilities in a short period.
Only with Arwen, or rather, Riona's hints did she understand what it meant to be a proxy.
It was similar to the concept of an Apostle.
Just as deities created Apostles, people that would serve as the deity's mouthpiece, it was possible for a person to become a conduit of power for a Branch.
Because the Branches of the Absolute One appeared to be the apex of supernatural capabilities, common sense dictated that what one would be capable of as a proxy would be more significant than one who took on the role of an Apostle.
