Source: Yu-Gi-Oh.JP Translation: Ygorganization
Consider the Looter a Compulsion that costs no mana to activate a huge distinction
Your opponent might have a creature removal spell or two they've been holding waiting for a target, or they might draw one, but one removal spell isn't getting it done
Giving your creature indestructible can be a lifesaver if you need other stax pieces (I am assuming if you play Boromir, Warden of the Tower , you are playing a stax deck) to stay alive, or if you just want to beat down someone and survive a board wipe
There are more specific sub-systems that get into the nitty gritty of Digivolution revolving around mechanics such as Talent, Cumulative Stats, and Bond
Although Yugi of Darkness was used as a Duel, Sugoroku did not know about Yugi of Darkness and passed it on to his grandson Yugi Muto, so appearing with Yugi Muto's skill can also be seen as an appropriate reproduction of the original work