Smooth fixing with Command Tower, Path of Ancestry, Exotic Orchard, Unclaimed Territory, Secluded Courtyard, fetches like Evolving Wilds/Terramorphic Expanse, and tri-lands (Seaside Citadel, Sandsteppe Citadel, Arcane Sanctum, Frontier Bivouac, Opulent Palace, Crumbling Necropolis, Savage Lands, Jungle Shrine, Mystic Monastery, Nomad Outpost)
The most obvious reason is that you guarantee getting the cards you wanted instead of trying to pull them by luck
Then, when this face-up card on the field is destroyed: Special Summon that banished monster to your side of the field
As well as appearing as one of the Nazgl cards, the Witch-king of Angmar features on a separate legendary creature card, mounted on his flying Fell Beast