They are great when you have artifact synergies going on

Alpha Power 9 Black Lotus - Alpha: Casting cost aligned down - Beta: Casting cost aligned up and slight right Ancestral Recall - Alpha: Black ink centered, blue dots in "crescent" - Beta: Black ink aligned up and to the right, no blue dots in "crescent" Time Walk - Alpha: Black ink aligned left, no blue dots in "crescent" - Beta: Black ink centered, blue dot in "crescent" Timetwister - Alpha: Black ink more centered - Beta: Black ink aligned down and to the left Mox Ruby - Alpha: Black ink aligned down and slight right - Beta: Black ink aligned up and slight right Mox Jet - Alpha: Black ink aligned down and slight right - Beta: Black ink aligned down and slight left - Extra Note: Two lines of dots in lower left corner in Alpha, One line in Beta Mox Pearl - Alpha: Black ink aligned down - Beta: Black ink aligned up Mox Emerald - Alpha: Black ink aligned down - Beta: Black ink aligned up Mox Saphire - Alpha: Black ink aligned slight right - Beta: Black ink aligned slight right (less than alpha) - Extra Note: Alpha Sapphire's have a unique print error (see next section)

They have to deal combat damage to a player get their trigger and if you whiff, you put a counter on it
Field of Ruin let control players drop Tectonic Edge and Spreading Seas for a free hate card in their manabase
If the numbers mean nothing to you, let me jog your memory
If you can threaten to sacrifice something, it makes that an even less attractive option, and even if you can't, your foes will still fear losing them in a suicidal attack, or even just being bludgeoned by their own pieces