Leather is, indeed, leather, but different treatments affect leather differently. Neat's foot oil is popular with baseball gloves because it softens the leather. That's a good characteristic for a baseball glove, but not necessarily for a saddle, which must support the rider's weight. If it becomes too soft, it will sag and eventually the saddle will be ruined. Wax-based products like Proofide and SnoSeal do not soften the leather, but rather protect it without softening. This allows the leather to accommodate to your shape without sagging or otherwise degrading.