But damage and loss of life are related. Any time you take damage, you lose life -- a rule that matters in several situations, and for a couple of cards in particular that care about amounts of life lost.
The ability of Children of Korlis, from Time Spiral, allows you to recoup a bunch of lost life -- and it doesn't specify "damage" you've taken this turn. It implies that it works for damage you've taken by its wording (and that reminder text helps). It would be quite a different card if it only worked for cards like Soul Feast!
That "damage causes loss of life" reminder text has appeared on only one other card. It's another card that would function very differently if it only cared about non-damage life loss.
This floating metal coffin from Darksteel effectively turns your permanents into a pseudo-life total, triggering whenever you lose life. But damage causes loss of life, so you can't ignore those Shocks and rampaging Grizzly Bears with the Tomb in play -- sorry, Lich fans!