If we disregard loot box definition for a second: Is there any reason NOT to display these drop rates? The only reason I can see is that they don’t have a nice place in-game to display the drop rates like they do with everything else. Yet, they added an “in-game but out-of-game” page accessible through the blue question mark on Shrines specifically for the new major orb of chaos dynamic. Why can’t the same thing be done for vault keys?
Technically, one could argue that event tiers don’t have drop-rates either, but that’s a topic for another thread.
Speaking of other threads, found another that discusses this same topic, from when Daemon gnome came out: Why are the drop rates for Vault and event shop troops not visible to players?