Glacier hasn't really seemed like it's worth it for me and looking over this calculator it's almost as expensive as Standard mode? Why would I use it over Standard, let alone Intelligent Tiering - Infrequent Access.
For example, for 50 GB it's showing a cost per month of $1.15 for Standard, which is correct (Standard is priced at ~$0.023/GB). For Deep Glacier, it's giving pricing of $1.05 (which is wildly incorrect, as the price for Deep Glacier is ~$0.00099/GB, meaning the monthly cost should say $0.05, or less than 5% of the Standard cost).