Is there any use for doing missions after you kill Orphan in FF13?

Im at Mission 51 ( Attacus) and am stuck. I'd like to do all missions if possible before killing Orphan, as Id feel a sense of accomplishment , aka more powerful when i face him

Or do i unlock something else, say maybe a storyline , if i leave the last 10 quests to do after Orphan is defeated. Collecting trophys is not something i want , unless theres something useful about the trophys im missing

thanks