Hes really good at holding equipment such as Sword of Hearth and Home or Umezawas Jitte to get extra triggers when he deals damage, but you can also use him to tutor up Skullclamp in your tokens deck and then immediately equip it to him to draw four cards when he dies
No one can try to destroy the creature you sacrificed to prevent you from casting this spell
But Greg, Ariel is a Super Rare and Gaston is an Uncommon, so it should be better. While the rarity of a card certainly can play a part in its value on the table, its not always 100% the case
Fell Stinger Deploy the Fell Stinger with its deathly scorpion's sting, and you can exploit (sacrifice another creature,) to evoke its 2 cards for 2 life ability, which can target any player
While theres a lot of synergy here, the cards are mostly strong independently, and the deck is designed to play a fair, interactive game that just happens to be able to gain infinite life with Urza and the Thopter Foundry / Sword of the Meek Combo, but mostly Urza, Oko, and Emry are all amazing standalone cards that require fairly different answers
There is also a detent mechanism to lock it in the open position