half-serrated knives are just a matter of personal preference. Fro years I would only carry combo-edges as EDCs, but as I moved to smaller knives (like the leek) I found more utility in a small PE blade than a combo blade. Unless you are going to be doing cutting of hard materials or rope, where a serrated edge would come in handy, I'd say a PE is more useful on a small knife. But having a combo edge certainly won't make it useless!
As for self-defense, a leek is way too small-handled to be thought of as a dedicated SD knife, especially with thin all-steel handles. It will owrk in a pinch of course. But if you are really thinking you need aknife proimarily for SD, you would do a lot better IMHO with a waved zytel-handled Spydie Delica or Endura, since they have more secure handles.