BE system traps the thinking player
There is no reason to disenchant if you don't have all champions. If I disenchant one of the many 450 shards in my inventory, I only get 93(?) out of 450 BE. Not only that, but I lose the 200-ish discount on the champion.
So essentially, disenchanting a 450 shard loses you about 300 BE.
At the same time, I don't want to unlock the champions because I never know when I might have barely enough BE after leveling to unlock a champ I actually want