Ideally, you can start out early with cards like Siren Stormtamer and Fathom Fleet Captain, then cast your commander on the same turn you plan on fulfilling her end step trigger
It scales up with your mana as you go later and later into the game from a nice midgame removal spell on one dork to a decent two removal dork for six mana a few turns later to three or four in late game, and getting that many removal spells on one card is incredibly strong
Scion of Calamity is a great card for any creature deck, but being a Dinosaur lets it enjoy a bunch of extra synergies in this deck
As of right now boast isnt a big enough mechanic to build a Commander deck around
Suffice to say, decks play these lands without downside most of the time, and they shine in 1- or 2-color decks
The Shepherd allows us to destroy artifacts and enchantments as long as we have a total of four creatures