Quote Originally Posted by DarthEnder View Post
Because Seastone+Darkness Fruit+Ocean << Seastone+Darkness Fruit+Ocean+Haki attacks+Elemental Weakness

It's at least two less weaknesses.

The tradeoff being that Macro seems to actually take damage, it just goes away. While Logia users usually just have things they aren't weak against pass through them.
Marco's "invulnerability" so far has been shown to be exactly the same type of invulnerability that Logia users enjoy.

Also I'm not sure how a Logia's cumulative weaknesses vs Marco's cumlative weaknesses has anything to do with Marco's phoenix power giving him the same restorative properties a Logia user has.