Parsing the specific goats - Rosh Chodesh, festivals, Yom Kippur - where each atones for specific things, and is where each thing can't usurp the atonement property of the others, or be used for other things. The particulars of the offering of the goats also make the difference in how and for what they each atone (sin-offerings have different procedures, including different locations of offering - inner and outer altars). Also, other animals that have been consecrated for the daily offerings - the consecration last for a year. If the animal develops a blemish, the sanctity can be redeemed, but what if there's no blemish, just the consecration expires. A parallel is drawn to ketoret, incense - in terms of desacralizing incense that wasn't used within the year of consecration.