There are a few fringe scenarios where you might want to intentionally cast a second legend after attacking with the first copy, just in case you need the blocker
Youll gladly give up the opportunity for Starting Town to enter untapped late in the game so you can avoid the life loss piling up in the red matchups
There are plenty of powerful lands in Modern, and having the ability to tutor them directly onto the battlefield - and without needing to play "do nothing" cards like Expedition Map - makes this one to keep an eye on
Elemental tribal players are spoiled for choice when it comes to their Commander, with Horde of Notions, Maelstrom Wanderer, Animar, Soul of Elements, Omnath, Locus of the Roil, and Omnath, Locus of Creation all being strong and viable choices for their Commander
Kasla makes it so anytime you cast another spell that has convoke, you get to scry two and then draw a card