Carrying solder rather than only heat. The angled cut creates an elliptical wetted face that holds a small reservoir of molten solder by surface tension, which the tip then delivers along a row of joints as it is drawn across them. It is the standard geometry for drag soldering fine-pitch surface-mount packages.

The shape of the face. A bevel is a plain angled cut giving a flat ellipse; a hoof has that face hollowed into a concave cup, so it holds noticeably more solder. Hoof tips suit larger fine-pitch packages and controlled removal of excess solder, while a plain bevel is easier to keep clean and control on smaller work.

Generous liquid or gel flux applied along the row of leads before the pass, well beyond what flux-cored wire supplies. The flux is what makes solder release onto the pads and leads while refusing to stay between them, so it is doing the selective work. Dragging without added flux is the most common cause of bridged joints.

Keep the face tinned at all times, clean on brass wool or a damp sponge rather than anything abrasive, and re-tin immediately before parking the iron. The wetted face is the working surface, so once oxidation stops it wetting evenly it will no longer hold or release a reservoir predictably, and drag passes become erratic long before the tip looks worn out.

Yes, and it is a capable general tip. The angled ellipse gives a good contact area and suits joints approached from the side or at a shallow angle, including through-hole work and wire. A chisel remains the more predictable default for general use because the flat face contacts the same way regardless of how the iron is rotated.