Its popularity stems not only from Luffys status as the beloved captain of the Straw Hat Crew but also from its exceptional competitive and aesthetic appeal
For one thing, life advantage doesnt translate well into other aspects of the game, such as having more cards in hand than your opponent or having better creatures on the battlefield
It also uses the graveyard to gain additional advantage over the course of the game in numerous ways - most notably by reanimating what has already died
The mana article for reference: Really well phrased
Weekly digests, tales from the communities you love, and more Cards like Tenuous Truce and Baird, Steward of Argive keep opponents from swinging at you and the likes of Bloodrot Apothecary (which pings enemies with toxic damage for each token they sacrifice) can literally kill people with kindness
As Gerry Thompson once said, I think this manabase is too good