Eleora is a coating that they put on Kanekalon fibers to make it softer. It's the equivalent of doing your hair with a spray conditioner - it adds a very natural texture to it. It's the most realistic looking of all the wig fibers, but as Kuukii-san said, the coating makes it resistant to some sorts of dye. If you are not going to dye it, it's fine. It's actually a very high quality fiber. (Technically not a different type of fiber - just a process the Kanekalon goes through.)
You don't have to worry about it looking unnatural or cheap. It actually looks the most similar to real hair out of all the synthetic blends out there.