Its best use seems to be either as a storm support card or in decks that can break the parity (with lots of cheap spells / creatures / cantrips that can cycle into each other), but Im honestly not a huge fan of it
While current Winota decks are all over the map in terms of color requirements, it feels like a Naya build that gives up some of the ability to hard-cast Agent of Treachery could have real potential
And with the number of legendary creatures that Wizards has printed in the last few years, youll never run out of options with this method
Legendary Creature - Rat Ninja Tasha, the Witch Queen Whenever you cast a spell you don't own, create a 3/3 black Demon creature token
There's sure to be tons of great value in other packs you can work off of as well, which will certainly make for a lot of fun casual gameplay during downtime at your LGS
But copying it isn't even that good, you are only doing this for two thopter tokens