My first thoughts on this were, "Why would I ever want a 'net zero' health transfer on my team instead of instead of a health transfer from the enemy to me with a silence attached?".
But... having the option is nice (when/if it actually works).
If Geist is in a duo lane and your ally is low and you're not, being able to bring them up from <20% health might mean the difference between losing the lane or winning.
I can also see an extreme niche case where you might Life Drain to an ally when you're about to Soul Exchange an enemy, even though I doubt that would happen more than 1 time in 20 games (probably less) it makes some logical sense to occasionally try.
