If it becomes a normal thing to proxy insanely expensive and powerful cards, youre all probably going to end up doing it
Narset Transcendent's -2 ability is its strongest, as it lets you get two casts of a spell for the price of one, since rebound lets you cast it again without paying its cost at the next upkeep
Of the three decks I have played, they are absolutely exceptional
I can't say it is an important aspect of the game to master but any gain in understanding you get for magic generally helps your overall game
What this means in practice for us is that, since 1999, almost every new Magic card print also exists in a much more rare shiny foil version
So, the inherent question of Mox JasperMox Jasper is the same as a generically played Mox TantaliteMox Tantalite: "What good is a Mox on turn four?" Well, I would answer that by saying it's all still pretty good at that point