There are not many four drops you need to kill that you are not just going to have lost to by the time you get your counters upto four
Crew's ability can only be activated at sorcery speed, making it useful as of main 1
[22] The Death card was canonically seen for the first time when Hawkins drew it in Chapter 1029
Mox Opal was banned in Modern relatively recently - in January 2020 - after Urza, Lord High Artificer decks became an abominable threat, aided by Oko, perhaps the most infamously broken Magic: The Gathering planeswalker ever printed
Imagine you just popped a Nevinyrral's Disk, played this and swung for four damage at someones face
There are a few staples that any Elf deck will love like: Elvish Archdruid Elvish Warmaster Overwhelming Stampede There are several high-power spells in the deck too, like Heroic Intervention and Asceticism to keep your creatures safe, and Genesis Wave to turn your mana into even more creatures