Purifying the entire world with making contained areas of Crimson/Corruption and Hallow is a very long and tedious task. And since citizens can live in Hallow, and normal enemies are not obstructed from spawning in Hallow.
Is it a good solution to make the entire world Hallow? Jungles will not be consumed because Hallow does not spread through mud and/or converts mud to dirt.
The only problem I see is that desert and the normal green biomes will no longer be existent (I can of course make quarantined areas of that too). Are there any unique features/items in the normal Green and Desert biomes?
Best Answer
Mummies spawn in desert biomes, if you're wanting to get an ankh charm (Blind fold) or light/dark shards keep the desert. You can also get the mummy costume. Antlions and vultures also spawn in the desert, you can use antlion mandibles for some items.
I'd recommend creating 'quarantined areas' (Possibly above ground) of desert, forest, and snow so that you can get the mobs that spawn there. (Frost Giants are quite a useful mob)
But hallowing everything, with the exception of 'quarantines', is probably a good idea if you don't want the Crimson/Corruption anymore.