The idea behind why is obvious
Real MTG card stock is roughly 280320 gsm, around 0.012 inch (0.3 mm) thick, with a smooth, coated surface
Additionally, there are still ways to get rid of Indestructible cards - they aren't totally immortal
The higher density of spells compared to creatures and greater mix of overall non-creature cards likely increase the decks ability to quickly hit delirium despite reducing how effectively the deck can leverage the threat of an early Mindwrack Demon
Instead, they slow the table down, answer threats cleanly, and turn small advantages into steady board control
Senu, Keen-Eyed Protector Before Orcish Bowmasters, if Senu, Keen-Eyed Protector had been printed, I might have suggested it was the most Modern playable card in this set, as unlikely as that might have been