My best guess is that they were having issues balancing other things and were using this card as the one with the most flexibility
Plus, Commander players usually like a diversity of colors and strategies, so even good colorless commanders receive some colored abilities here and there to expand players options like weve seen on Golos, Tireless Pilgrim or Ulalek, Fused Atrocity
And because these effects are so universal, Greaves will easily find a place in any deck, so long as it plays creatures
If you want one card for your Atraxa deck, its probably Gatewatch Beacon
But should you play all four copies of that removal spell or creature, or should you just include three, two, or even one
Cards That Are Cheaper to Plot I think that cards that are cheaper to plot than to cast normally are the most approachable designs when first trying to understand the mechanic