Originally abused with Vesuva in its Standard days, this mechanic is pretty valuable, allowing you to abuse the legend rule to fix your mana while thinning your deck
The chosen recipient must be able to legally be enchanted by the Aura, so a player or permanent with protection from one of the Aura's qualities can't be chosen this way
Narci is a great commander to have around, along with Tom BombadilTom Bombadil, Sigurd, Jarl of RavensthorpeSigurd, Jarl of Ravensthorpe, and Eivor, Wolf-KissedEivor, Wolf-Kissed (though the latter two cards can't run Binding) because Sagas are a blast to play with and getting to build around them offers yet another quirky deckbuilding pathway in the format
Of course, if your entire deck revolves around one of these doublers, I advocate you run just Doubling Season and a few specific tutors like Idyllic Tutor before I ever sign off on running Primal Vigor
We lack the Sol lands that enable its early deployment in Legacy and Vintage (although Simian Spirit Guide does its best impression), but a format as efficient as Modern certainly boasts a large number of one-dropsmaking Chalice a potential ten-for-one (or more!) against any number of strategies
Some of you are probably still looking at me wondering why paying effectively 5 mana (when you include Ardenvale itself) for a 1/1 is worth your time, and if this effect was stapled to anything except a land, Id be right there with you