Not only do they help with your color fixing, there are tons of other benefits fetch lands provide as well
You get a power boost whenever it attacks or enters in the form of +1/+1 counters, but the real charm is that it staples a free token onto every vampire you cast
For example, your Village Rites gets you another creature to play next
That does some wild stufffor example, it gets Marsh Flats back twice for actual land ramp in Orzhov, it lets you feed cards like Dusk Legion Zealot into a Warren Soultrader multiple times, or it wrings the most value possible from cards like Boromir, Warden of the Tower and Dauthi Voidwalker
And the enchantment side is just so good
Card Name The Wandering Minstrel Mana Cost Type Legendary Creature Human Bard Rarity Rare rules Text Lands you control enter untapped