Fragile, yes, but kinda cute, too
Now these formats, often encourage having a bunch of dudes in play, waiting to draw your enabler, or waiting till turn 4-5 to drop your lord, people will sit on their boardstate and a lot of these decks don't feel like they are encouraging you to stock up on Jace's Ingenuity to refill your hands
Since it can snowball so easily with just a few tokens, Magnus will always have a place in Spellslinger decks
The key limitation to keep in mind is that the enchantment sacrifices itself at the beginning of the end step, so youre working on a clock
But honestly, every artist who puts their life into Magic deserves all support you can give them, so order that print or playmat and admire it in every game
Testing with Izzet Phoenix featuring one copy of The Royal Scions led me to believe that it is likely one of the best cards in the archetype if you can build around it