The life gain played by normal decks to sure up their matches against agro decks has to minimally impact the deck in their other match ups however in decks that are really abusing life as a resource such as Necropotence you typically need some life gain just to enable the continued use of your effects
Mill never had the right support to dominate any format, and if the milling failed, the mill deck would be too far behind in the game and lose but in Commander, even with 99-card decks, mill might work with creatures like Bruvac, the Grandiloquent around
Each guild offers its own distinct mechanics and playstyle, from the control-focused Azorius to the chaotic aggression of Rakdos and the experimental growth of Simic
This is also great against land removal for you or others as your stuff dies you can still tap for it, so if your foe uses Vindicate to destroy your Cabal Coffers when you control Urborg you can just tap this to make that mana
The idea is to get the most bang for your buck so you can reinvest those new found dollars into MORE cards, right
For example, Amber is meant to be a support Ink type, whereas Amethyst is meant to be more fragile ability users
