You don't have to pay $150 for retrieval of 60GB. And you don't do long-term storage for X TB / 5 TB * $150. You might have to rent space in someone elses datacenter to put your own external backup... or you could pay Amazon for Glacier and not deal with maintenance etc. Might be worth it even if you have infrastructure for all data that isn't glacier-cold.
You don't have to pay $150 for retrieval of 60GB. And you don't do long-term storage for X TB / 5 TB * $150. You might have to rent space in someone elses datacenter to put your own external backup... or you could pay Amazon for Glacier and not deal with maintenance etc. Might be worth it even if you have infrastructure for all data that isn't glacier-cold.