Avacyn's Memorial is essential for protecting your 5-color commander and your other legendary permanents because theyll gain indestructible
Getting a free reanimate effect every turn is a solid way strategy, letting you make use of some great enter the battlefield triggers and be a little looser with your attacks
You can also use it to take advantage of any potential token synergy like Doubling Season, or even abuse Kodama of the East Trees ability to play even more lands
It was the first major, on-curve creature with a powerful ability to boot (compared to other cards of a similar cost, like Nettletooth Djinn, that had weaknesses instead)
Those effects are welcome in any Simic Commander deck, even if she isnt that exciting to build around
You can clearly distinct between the black lines of the expansion symbol and the printed color dots