The card specifies what you do with the land, sometimes very plainly like the transformed Rona, Rona, Tolarian Obliterator
This is nice, because you can learn the ropes without getting pummelled by higher-level players
It can go in any deck, Angels or not, and is a great tool to manipulate combat
For example, Silhana Ledgewalker and Loxodon Smiter
Some of these cards feel like win conditions in their own right, see Necromancer's Covenant Graveyard hate is usually pretty boring, people who wouldn't normally put some in might do so now because they found some exciting options in this list
Along similar lines to the above strategy, cards like Goro-Goro and Satoru and Ojer Kaslem, Deepest Growth with triggers when dealing combat damage to a player can greatly benefit from additional combat phases