Cards that passively scale with time and synergize well with support pieces are commonly valued by Commander players, which explains its listing between 13 and 17
Add these two cards in a single one and we have edict/life drain in the same card slot
Lifegain effects fall into two categories: single-effect, big bursts of lifegain from cards like Feed the Clan, and incidental lifegain from cards like Soul Warden and Kambal, Consul of Allocation
This would give me a much more direct path to victory
Two mana to discard two cards is also just an incredible price, and is especially potent when Hymn to Tourach follows a turn-one discard spell like Thoughtseize or Inquisition of Kozilek
If you use the plus-one ability to equip it, it will get six counters when Cloud attacks, allowing you to remove ten loyalty for ten mana the next turn