POTD Fixed Party Save Slots

So here's a question that came to mind, why do all members need to have a fixed party save slot in their slot? What purpose does it serve when if just one person erases said save none of the other 3 can use it. While you offer the ability to set fixed party matched party, this means nothing for 100+ progress.

So my question is, is it really necessary for all 4 people to have the same save? Why not just have someone set as Leader with the names of the other 3 members. Would this not work? I don't really see why it shouldn't be possible since this would allow players the ability to have more saves available and not feel constricted by the two they currently have.